JPH0948825A - Polymer having high acid value, its use and production process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject polymer composed of an α, β-unsaturated carboxylic acid monomer and a vinyl monomer, having a specific property, causing little variation of the physical properties with temperature, soluble in water and/or an alkali and having excellent transparency. SOLUTION: The objective polymer is produced by polymerizing (A) an α, β-unsaturated carboxylic acid monomer and (B) a vinyl monomer in such a manner as to obtain a polymer having an acid value of >=70mgKOH/g and a parallel light transmittance of >=70% and giving a differential curve having two or more peaks in the range of -80 deg.C and +120 deg.C by differential scanning calorimeter. Preferably, the component A is acrylic acid and/or methacrylic acid and the ratio of the component A is 9-40wt.%. An alkyl acrylate and/or an alkyl methacrylate preferably account for >=30 wt.% of the component B. Preferably, the objective polymer is further incorporated with a polyvalent metal salt such as magnesium acetate or zinc carbonate to improve the mechanical strength, etc.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polymer having excellent transparency and having a specific acid value and a glass transition point distribution, its use, and its production method. The polymer of the present invention is useful when used in various molding materials, particularly in the fields of films, sheets and the like. The film of the present invention is particularly useful when used as a packaging bag, an adhesive (adhesive) sheet, a window-opening envelope and various processed papers, and can also be used as a laminated film with other various resins. The polymer of the present invention can also be used as a coating agent and is useful when coated on various papers and films.

[0002]

2. Description of the Related Art Generally, most vinyl polymers undergo a glass transition in a narrow temperature range of about 20 ° C., and a differential curve obtained by measurement with a differential scanning calorimeter (hereinafter abbreviated as DSC) has a glass transition temperature. It has only one peak corresponding to (hereinafter, abbreviated as Tg). Particularly in the case of an acrylic film or the like, the polymer composition constituting the film has a Tg of 20 to 40 ° C. Therefore, these films also have the problems that the strength changes greatly with temperature, they are easily blocked at high temperatures, they have low flexibility at low temperatures, and they have low tensile strength and tear strength.

Conventionally, there is an adhesive (adhesive) sheet composed of a film such as polyethylene terephthalate, polypropylene and polystyrene and an adhesive (adhesive), and such a sheet is used as a label for a glass bottle or the like, but is simply an alkali. Since the label cannot be removed only by washing, there is a problem that it is very difficult to recycle the glass bottle. Also, Japanese Patent Application Laid-Open
No. 161045 discloses an example in which the above-mentioned film is used as a window portion film of a windowed envelope. However, since none of these films is water-soluble and / or alkali-soluble, the envelope is recovered and used as waste paper. It is an obstacle when doing. For a windowed envelope, see Japanese Patent Laid-Open No.
JP-A-161045 and JP-A-7-41585 disclose the use of polyvinyl alcohol-based films, but these films have insufficient water resistance, or take a long time to dissolve, or There is a problem that it easily blocks due to moisture absorption.

Under these circumstances, vinyl polymers are also water-soluble and / or alkali-soluble.
With recycling in mind, it can be used for various purposes other than labels, so it has recently become water-soluble and / or
Alternatively, the need for alkali-soluble vinyl polymers is increasing. As a vinyl-based polymer having one Tg, for example, JP-A-1-165685 discloses a film and a label of a (meth) acrylate / (meth) acrylic acid polymer which is soluble in alkaline water. Further, in Japanese Patent Laid-Open No. 5-96689, α, β-
Disclosed is a laminated paper in which an acrylic acid ester-based polymer containing an unsaturated carboxylic acid or a vinyl group-containing acid anhydride as a main component, and a plastic layer soluble in an alkaline solution is laminated on paper. All of these films, labels and laminated papers have the above problems (1) to (3) because the polymer has only one Tg. As a method for solving these problems, it is conceivable to design a polymer having not only one Tg but a plurality thereof.

An acrylic resin composition having a plurality of Tg's has a Tg of 2 as disclosed in JP-A-59-215365.
0 ~ 50 ℃ acrylic resin emulsion and Tg-10
A resin composition mainly composed of a mixture with an acrylic resin emulsion at -15 ° C is disclosed. Since this resin mixture has multiple Tg's, it is excellent in peelability and adhesion, but it is not uniform at the molecular level because it is a mixture rather than a single polymer. Therefore, it is obtained from this resin mixture. The resulting film has poor transparency, is easily whitened when pulled, and has low tear strength. Moreover, this acrylic resin emulsion is neither water-soluble nor alkali-soluble.

Further, as a polymer which is considered to have a plurality of Tg's other than the blended product, JP-A-5-1790 is used.
No. 92 and Japanese Patent Publication No. 6-51860. These techniques relate to emulsion polymerization. Generally, the monomers that can be used in emulsion polymerization are only a part of the polymerizable monomers, and therefore there are major restrictions on the design of the polymer, and the physical properties of the resulting coating are also limited. .

Further, in the above-mentioned JP-A-5-179092 and JP-B-6-51860, an emulsion polymer having a so-called "core-shell" structure is synthesized by a multistage emulsion polymerization method. When a coating is prepared using an emulsion polymer having a different "core-shell" structure, the shell is usually fused, but the core remains almost unchanged. The resulting coating has a heterogeneous structure with the core dispersed in the continuous phase originating from the shell.
Therefore, the coating film formed by using the emulsion polymer having the "core-shell" structure generally has problems such as low mechanical strength and easy whitening during pulling or water absorption. The emulsion polymers disclosed in JP-A-5-179092 and JP-B-6-51860 are:
It mainly relates to a polymer that forms a coating film, etc., but as an emulsion polymer for use in paints, etc., it has improved mechanical strength and water resistance as compared with conventional ones, but it is a packaging bag or label base material. As a film used in a field in which transparency is particularly required, transparency and mechanical strength are insufficient, and whitening during water absorption is also a problem.

Furthermore, the emulsion polymers disclosed in JP-A-5-179092 and JP-B-6-51860 are neither water-soluble nor alkali-soluble. Further, as another method for providing both flexibility and tensile strength, a polymer that causes a glass transition in a wide temperature range may be used. As a method for obtaining such a polymer, there is a method called a normal power feed method, which is disclosed in Japanese Patent Laid-Open No. 50-63085. The polymer obtained by this method shows one broad peak in the differential curve obtained by measurement with DSC. The vinyl polymer for a film obtained by this method inevitably has a temperature of 20 ° C. to 4 ° C. in view of the balance of tensile strength and flexibility.
A large amount of a polymer having Tg at 0 ° C. is contained as a component. Therefore, the polymer for a film has a problem that the mechanical strength or the like remarkably changes in the temperature range where the film is usually used.

[0009]

[Problems to be Solved by the Invention] Japanese Patent Publication No. 6-51860
When an attempt is made to synthesize a polymer having a high acid value which becomes water-soluble and / or alkali-soluble by using the emulsion polymerization method described in Japanese Patent Publication No. Part of the monomer dissolves in water and polymerizes in aqueous solution. In this way, a polymer containing more α, β-unsaturated carboxylic acid units than by-product is produced as a by-product, and as a result, the water resistance of the polymer becomes worse than that in the original design. Further, such a polymer containing a large amount of α, β-unsaturated carboxylic acid units has a solubility parameter greatly different from that of another polymer produced simultaneously by emulsion polymerization, and is incompatible. The resulting polymer is not entirely homogeneous, opaque and has poor mechanical strength.

In view of such circumstances, the problem to be solved by the present invention is that there is little change in physical properties due to temperature change, it has water solubility and / or alkali solubility, it is excellent in transparency, and when it is pulled or when it absorbs water. It is to provide a polymer with less whitening. Another problem to be solved by the present invention is
A coating agent that is printable, does not easily block at high temperatures, has high flexibility at low temperatures, is water-soluble and / or alkali-soluble, has excellent transparency and gloss, and can form a coating layer with little whitening when pulled or absorbing water. Is to provide.

Still another problem to be solved by the present invention is that printing is possible, there is little change in strength due to temperature change, it is difficult to block at high temperature, it has high flexibility at low temperature, high tensile strength and tear strength, and It is intended to provide a film, a packaging bag, and a pressure-sensitive adhesive (adhesive) sheet, which is less likely to be whitened when water or water is absorbed, is water-soluble and / or alkali-soluble, and is excellent in transparency.

Still another problem to be solved by the present invention is that it is printable, has little strength change due to temperature change, is hard to block at high temperature, has high flexibility at low temperature, has high tensile strength and tear strength, and has high tensile strength. (EN) A window-opening envelope which has less transparency during water absorption and water absorption, is water-soluble and / or alkali-soluble, and has excellent transparency, and can be easily recovered and used as waste paper.

Still another problem to be solved by the present invention is a film which is printable, hard to block at high temperature, highly flexible at low temperature, water-soluble and / or alkali-soluble, and excellent in transparency and gloss. It is an object of the invention to provide a renewable processed paper and a renewable release paper having layers. Still another problem to be solved by the present invention is printability, little change in strength due to temperature change, difficulty in blocking at high temperature, high flexibility at low temperature, high tensile strength and tear strength, white even when pulled. It is an object of the present invention to provide a method for easily and efficiently producing a polymer that is hard to form, has water solubility or alkali solubility, and has excellent transparency.

[0014]

The polymer of the present invention comprises α,
A polymer having an acid value of 70 mgKOH / g or more obtained by polymerizing a β-unsaturated carboxylic acid monomer and a vinyl-based monomer, which is obtained by measurement with a differential scanning calorimeter (DSC). The curve has two or more peak tops between −80 and 120 ° C., and the parallel light transmittance is 70% or more.

The differential curve is between −30 and 20 ° C.
Having a peak top at each of 40 to 100 ° C.,
The parallel light transmittance is preferably 80% or more. 30% by weight or more of the vinyl-based monomer is an acrylic acid alkyl ester and / or a methacrylic acid alkyl ester, which is preferably obtained by polymerization in a non-aqueous system.

The α, β-unsaturated carboxylic acid monomer is acrylic acid and / or methacrylic acid,
The structural unit of the β-unsaturated carboxylic acid monomer is 9 in the polymer.
It is preferable that the content is at least wt%. It is preferable to further include a polyvalent metal salt. The coating agent of the present invention contains the polymer and an organic solvent.

The film of the present invention contains the above polymer.
The packaging bag of the present invention comprises the film. The adhesive (adhesive) sheet of the present invention comprises the film and an adhesive (adhesive). A windowed envelope of the present invention includes an envelope body having a window portion and the film closing the window portion.

The recyclable processed paper of the present invention comprises a paper base material and the film laminated on the paper base material. The releasable release paper of the present invention comprises a paper base material, the film laminated on the paper base material, and a release agent layer laminated on the film. The method for producing a polymer of the present invention comprises a plurality of monomer components comprising at least 9% by weight or more of an α, β-unsaturated carboxylic acid monomer and one or more other vinyl monomers (provided that Each monomer component gives a polymer having a different glass transition temperature), and a method for producing a polymer by non-aqueous polymerization using a multi-step polymerization process, wherein at least one monomer component A It is characterized in that the step of polymerizing a part and the rest of the monomer component A and the other monomer component are polymerized while sequentially changing the compounding ratio in the polymerization system.

As a method of sequentially changing the compounding ratio,
It is preferable to carry out further while adding or dropping the other monomer components into the system in which the monomer component A is non-aqueous polymerized to a polymerization rate of 20 to 80%. It is preferable to further include a step of mixing a polyvalent metal salt.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Polymer having high acid value and process for producing the same The polymer of the present invention is an acid obtained by polymerizing an α, β-unsaturated carboxylic acid monomer and a vinyl monomer. Value is 70mgK
It is a polymer of OH / g or more. Specific examples of the α, β-unsaturated carboxylic acid monomer include α, β-such as acrylic acid, methacrylic acid, maleic acid, itaconic acid and fumaric acid.
Unsaturated carboxylic acid; α, β-unsaturated carboxylic acid anhydride such as maleic anhydride and itaconic anhydride; α, β-unsaturated dicarboxylic acid monoester such as maleic acid monoester, fumaric acid monoester and itaconic acid monoester Mention may be made of esters. Two or more kinds of these α, β-unsaturated carboxylic acid monomers may be used in combination.

As the α, β-unsaturated carboxylic acid monomer,
When using acrylic acid and / or methacrylic acid,
It is preferable because the flexibility and toughness are improved. Specific examples of the vinyl monomer include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate,
Esters of monohydric alcohols having 1 to 18 carbon atoms such as butyl methacrylate and stearyl methacrylate with acrylic acid or methacrylic acid; nitrile group-containing vinyl monomers such as acrylonitrile and methacrylonitrile; amide groups such as acrylamide and methacrylamide. Vinyl-containing monomer; Hydroxyl acrylate, hydroxypropyl methacrylate, and other hydroxyl-containing vinyl monomers;
Epoxy group-containing vinyl monomers such as glycidyl methacrylate; α, β such as zinc acrylate and zinc methacrylate
-Metal salts of unsaturated carboxylic acids; aromatic vinyl-based monomers such as styrene and α-methylstyrene; aliphatic vinyl-based monomers such as vinyl acetate; vinyl chloride, vinyl bromide, vinyl iodide, vinylidene chloride Halogen-containing vinyl monomers such as; allyl ethers; maleic acid derivatives such as maleic anhydride, mono- and dialkyl esters of maleic acid;
Fumaric acid derivatives such as mono- and dialkyl esters of fumaric acid; maleimide derivatives such as maleimide, N-methylmaleimide, stearyl maleimide, N-phenylmaleimide, N-cyclohexylmaleimide; mono- and dialkyl esters of itaconic acid, itaconic amides, itaconimide And itaconic acid derivatives such as itacone amide esters; alkenes such as ethylene and propylene; and dienes such as butadiene and isoprene. You may use together 2 or more types of these vinyl type monomers.

It is preferable to use an acrylic acid alkyl ester and / or a methacrylic acid alkyl ester as the vinyl-based monomer because a film excellent in flexibility, toughness, gloss, weather resistance and transparency can be obtained. Also,
It is preferable that the amount thereof is 30% by weight or more based on the total amount of the vinyl-based monomer used because the flexibility, toughness, gloss, weather resistance and transparency are further improved. Furthermore, it is preferable that the acrylic acid alkyl ester and the methacrylic acid alkyl ester are esters of a monohydric alcohol having 1 to 18 carbon atoms and acrylic acid or methacrylic acid, because flexibility, toughness, gloss, and weather resistance are further improved. .

When the ratio of the α, β-unsaturated carboxylic acid monomer to the total amount of the α, β-unsaturated carboxylic acid monomer and the vinyl monomer is 9% by weight or more of the total amount. If so, the structural unit of the α, β-unsaturated carboxylic acid monomer obtained by polymerizing the α, β-unsaturated carboxylic acid monomer is 9% by weight or more in the polymer, and the solubility is sufficient. It is preferable because such a polymer can be obtained. It is more preferable that the proportion of the α, β-unsaturated carboxylic acid monomer used is 9 to 40% by weight based on the total amount because a polymer having a good balance of deliquescent property, water resistance and flexibility can be obtained.

Since the polymer of the present invention has a high acid value, it is water-soluble and / or alkali-soluble, and its acid value is 70 mgKOH / g or more. When water resistance is required, it is preferably 70 to 250 mgKOH / g. The specific method for measuring the acid value is not particularly limited. A method of titration with a 1N aqueous sodium hydroxide solution may be used.

The number average molecular weight of the polymer of the present invention is 1000.
It is 0 or more. When the polymer is used for applications such as a film, it is preferable that the number average molecular weight is 10,000 to 500,000 in view of moldability. In the polymer of the present invention, its Tg distribution is the most important. The distribution of Tg of the polymer is judged from the differential curve obtained by measuring with DSC. Generally, a differential curve obtained by measurement with DSC has many noises and minute peaks, but the peak top in the present invention is clearly a peak having a size recognized as a main peak. , Is the part showing the largest differential value.

The main peaks mentioned above are 3 when the peak top height is 50 μW / min or more and the half width is 5 ° C. or more.
It is preferably 0 ° C. or lower. The reason why the full width at half maximum is preferably 5 ° C. or more is that many peaks derived from additives and the like have small full width at half maximum of less than 5 ° C. and can be distinguished from peaks derived from the polymer of the present invention. is there.

In the above-mentioned differential curve, the height of the peak from the baseline at each temperature represents how much the endothermic amount per unit time at that temperature is changing, and that temperature is Tg. It is considered to indicate how many individual component polymers are Therefore, by comparing the heights of the peaks, it is also possible to compare the number of component polymers whose temperature is Tg. It is also possible to judge the ratio of the individual component polymers having a temperature of Tg in the whole. Therefore, DSC measurement is very important,
It is important to perform measurement under constant conditions. In addition, DSC
There is no particular limitation on the specific method of measuring
For example, DSC220C manufactured by Seiko Instruments Inc.
, Using a 10 mg sample under a nitrogen atmosphere. Examples of the measurement conditions include a method of heating to 150 ° C., holding for 5 minutes, quenching to −100 ° C., holding for 5 minutes, and then heating to 150 ° C. at 10 ° C./min. Gives a DSC curve and a DSC derivative curve. The baseline for the differential curve is drawn by connecting the positions where the differential value is 0 μW / min.

In the polymer of the present invention, the differential curve obtained by measuring with DSC has two or more peak tops between −80 and 120 ° C. The differential curve is −30 to 2
It is preferable to have peak tops between 0 ° C. and 40 to 100 ° C., respectively. When the peak top on the low temperature side is in the range of −30 to 20 ° C., a polymer-containing film or the like has high flexibility at low temperature, high tear strength, and blocking is not a problem. When the peak top on the high temperature side is between 40 and 100 ° C., the polymer-containing film or the like has strong tensile strength and stiffness, and blocking does not occur.

In the differential curve, the ratio of the height of the peak top on the low temperature side and the peak top on the high temperature side from the baseline [the height of the peak top on the low temperature side / the height of the peak top on the high temperature side]. Have a preferable ratio depending on the use. For example, when the polymer of the present invention is used for an adhesive (adhesion) sheet used for a film, a label, etc., the mechanical strength and the blocking resistance are 1/9 to 6/4. It is preferable from the balance. More specifically, 2/8 to 6/4 is preferable when tear strength, elongation or flexibility at low temperature is important, and 1/9 to when tensile strength or blocking resistance is important.
4/6 is preferable.

Further, the peak top of the differential curve obtained by DSC may exist between 20 and 40 ° C. However, if the peak is too large, the film obtained from the polymer will be temperature-sensitive. It becomes large, and changes in mechanical strength and the like are large in the temperature range normally used. Therefore, the ratio of the area occupied by the peak between 20 and 40 ° C is
It is preferably 50% or less of the total peak area.

However, when the compatibility between the component forming the peak top on the low temperature side and the component forming the peak top on the high temperature side is not good, it is a component having an intermediate composition between the two components. The presence of a component forming a peak between -40 ° C is preferable because it acts as a compatibilizing agent for both components and sufficient transparency can be obtained. In this case, the ratio of the area occupied by the peak between 20 and 40 ° C. in the differential curve is 5% or more of the whole, and more preferably 10% of the whole.
% Or more is preferable.

The polymer of the present invention is characterized by having a high transparency because it has a homogeneous structure. The transparency is, for example, the parallel light transmittance of visible light of 400 to 700 nm measured using a turbidimeter equipped with a halogen lamp and a polarizing filter (ND-101DP of Nippon Denshoku Industries Co., Ltd.). Evaluated by value. The parallel light transmittance is
It is measured by irradiating visible light in the thickness direction on a film test piece having a thickness of 65 μm in which the state of the sample was adjusted by leaving it in an atmosphere of 23 ° C. and 65% RH for 24 hours. In addition,
No special processing such as embossing that modifies the surface is applied to the test piece used for measurement.

The parallel light transmittance of the polymer of the present invention is 70.
% Or more. Further, when it is used for an application requiring transparency, the parallel light transmittance is more preferably 80% or more. However, since the parallel light transmittance may differ in the measurement result depending on the condition of the sample, it is necessary to evaluate it under the same conditions. When the polymer of the present invention further contains a polyvalent metal salt, it has high mechanical strength (tensile strength and tear strength), is less likely to cause blocking, and has more stable strength and dimensional characteristics against changes in temperature or humidity. This is preferable because

Specific examples of the polyvalent metal constituting the polyvalent metal salt include beryllium, magnesium, calcium, strontium and barium group IIa metals; zinc, cadmium and mercury group IIb metals; boron, aluminum,
Mention may be made of Group IIIb metals of gallium, indium and thallium. Two or more of these polyvalent metals may be used in combination. Among them, at least one of the polyvalent metals selected from the group consisting of magnesium, calcium and zinc
Being a kind of metal, the elongation characteristics of the film containing the polymer,
It is preferable from the viewpoint of water resistance, transparency and economy.

Specific examples of the polyvalent metal salt include magnesium acetate, calcium acetate, zinc acetate, cadmium acetate,
Acetates such as aluminum acetate; carbonates such as magnesium carbonate, calcium carbonate, zinc carbonate, cadmium carbonate, and aluminum carbonate; oxalates such as magnesium oxalate, calcium oxalate, zinc oxalate, cadmium oxalate, and aluminum oxalate Phosphates such as magnesium phosphate, zinc phosphate, cadmium phosphate, and aluminum phosphate; and stearate salts such as magnesium stearate, calcium stearate, zinc stearate, cadmium stearate, and aluminum stearate. .

Among the polyvalent metal salts, magnesium acetate,
It is preferable to include calcium acetate, zinc acetate, magnesium carbonate, calcium carbonate, zinc carbonate, magnesium stearate, calcium stearate, and zinc stearate from the viewpoints of elongation, water resistance, transparency and homogeneity of the polymer-containing film. As the polymer of the present invention, a polymer obtained by polymerizing in a non-aqueous system is preferable. Examples of the non-aqueous polymerization include solution polymerization or bulk polymerization in which an organic solvent is used and water is not used. The reason why the reaction in a non-aqueous system is preferable is that there are restrictions on the monomers that can be used in polymerization in an aqueous solution, and a film containing a polymer having a high acid value obtained by emulsion polymerization in an aqueous system has a heterogeneous structure. Because of this, transparency is poor, whitening easily occurs, and strength is not sufficient. Specific examples of the polymerization method include anionic polymerization,
Although cationic polymerization and radical polymerization can be mentioned, radical polymerization is preferred.

The radical polymerization initiator used in radical polymerization is not particularly limited, and specific examples thereof include
Azo initiators such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile); peroxides such as benzoyl peroxide and di-t-butyl peroxide Examples thereof include system initiators. Two or more of these radical polymerization initiators may be used in combination.

The solvent used in the solution polymerization is not particularly limited as long as it does not interfere with the radical polymerization reaction and is a solvent other than water. Specific examples thereof include alcohols such as methanol, ethanol and isopropyl alcohol; benzene, Aromatic hydrocarbons such as toluene; ketones such as acetone and methyl ethyl ketone; aliphatic esters such as ethyl acetate and butyl acetate. Two or more of these solvents may be used in combination.

As the reaction vessel used for producing the polymer of the present invention, any reaction vessel can be used. Specific examples of the reaction vessel include a conventional tank reactor, a kneader, a tubular reactor such as a static mixer, and the like. A plurality of such reactors can be used as needed. Also, a dropping tank is used as needed.

The pressure in the reaction vessel at the time of producing the polymer may be any of reduced pressure, normal pressure and increased pressure. The method for producing the polymer of the present invention includes, for example, a plurality of monomers composed of at least 9% by weight or more of α, β-unsaturated carboxylic acid monomer and one or more other vinyl monomers. A method for producing a polymer in which components (however, each monomer component gives a polymer having a different glass transition temperature) is subjected to non-aqueous polymerization using a multi-step polymerization process, wherein at least one monomer component is used. Especially, if it is characterized by polymerizing the step of polymerizing a part of A and the rest of the monomer component A and other monomer components while sequentially changing the compounding ratio in the polymerization system. There is no limit.

Here, the Tg of the polymer provided by each monomer component in the present invention means, in the case where the monomer component is composed of only one kind of monomer, each generally accepted single weight. It is the Tg of coalescence. Further, when the monomer component is composed of two or more kinds of monomers, a homopolymer (A,
Bg, C, ...) Tg values (Tga, Tgb, Tg
c, ... The unit is Tg (K) calculated by the following formula (1) that is commonly used when predicting the glass transition point of a copolymer using K).

Tg = 1 / (a / Tga + b / Tgb + c / Tgc + ...) (1) where a, b, c, ... Are the respective monomers A, B, C ,.
··· is the weight fraction, and a + b + c + ... = 1. A specific example of the calculation using the formula (1) is as follows: in the case of a monomer component consisting of 80 parts by weight of ethyl acrylate, 10 parts by weight of acrylic acid and 10 parts by weight of methyl methacrylate, each homopolymer Since the Tg of is 249K, 376K and 378K, the calculated Tg is: Tg = 1 / (0.8 / 249 + 0.1 / 376 + 0.1
/ 378) ≈267K≈−6 ° C.

As the method for producing the polymer of the present invention, for example, the following method I or II is preferable because it can be produced more easily and efficiently. Method I: In the above production method, the monomer component A has a polymerization rate of 20 to 80% as a method of sequentially changing the compounding ratio.
A method in which the other monomer components are added dropwise or dividedly into the non-water-polymerized system up to and further added. Specifically, while adding another monomer component B that gives a polymer having a Tg different from that of the monomer component A to the system obtained by non-aqueous polymerizing the monomer component A to a polymerization rate of 20 to 80%, Polymerization is further carried out, and then polymerization is further carried out while dropping or separately introducing other monomer components C, D, etc. which give a polymer having a Tg different from that of the monomer components A and B, if necessary.

The Tg of the polymer provided by the monomer component A and the Tg of the polymer provided by the other monomer components C and D are 30.
A difference of not less than 0 ° C. is preferable because various physical properties can be provided together. Specifically, when the polymer of the present invention is used particularly for a film, one T in the polymer provided by the monomer component A and the other monomer components B, C and D is given.
When g is −30 to 20 ° C. and Tg of the other polymer is 50 to 120 ° C., the obtained film has high tensile strength and blocking is not a problem, which is preferable. Further, each of the monomer components A, B, C, D and the like contains 7% by weight or more of an α, β-unsaturated carboxylic acid monomer, and between these monomer components, α, When the difference in the content of the β-unsaturated carboxylic acid monomer is 10% by weight or less, the resulting polymer has good compatibility, so that the transparency becomes particularly excellent, and the solubility, water resistance, etc. With respect to the physical properties of (1), a polymer having uniform physical properties is obtained, which is preferable. For example, in the case where the monomer component A contains 10% by weight of α, β-unsaturated carboxylic acid monomer, α,
The content of the β-unsaturated carboxylic acid monomer is preferably 20% by weight or less, and the content of the α, β-unsaturated carboxylic acid monomer such as the monomer component A and the other monomer component B is When the contents are the same, the transparency of the obtained polymer is highest, which is preferable.

Method II: Monomer Component A and Monomer Component A
Is another monomer component B which gives a polymer having a different Tg,
C, D, etc. are individually polymerized to a polymerization rate of 20 to 80% by non-aqueous polymerization, and then the contents of the reaction container of the monomer component A are added to the reaction container of the monomer component A. Polymerization is further carried out while dropping or adding. In the method II as well as the method I, the T
T of g and a polymer given by other monomer components C, D, etc.
When g is different by 30 ° C. or more, it is possible to combine various physical properties, which is preferable.

Specifically, when the polymer of the present invention is used particularly for a film, one Tg in the polymer given by the monomer component A and the other monomer components B, C and D is −
When the temperature is 30 to 20 ° C. and the Tg of the other polymer is 50 to 120 ° C., the obtained film has high tensile strength and blocking is not a problem, which is preferable.
Also in the method II as in the method I, the monomer components A, B, C, D, etc. are all 7% by weight or more of α, β.
-A polymer obtained which contains an unsaturated carboxylic acid monomer and the difference in the content of the α, β-unsaturated carboxylic acid monomer between these monomer components is 10% by weight or less. It has a good compatibility, so that it is particularly excellent in transparency and is a polymer having uniform physical properties such as solubility and water resistance, which is preferable. For example, when the monomer component A contains 10% by weight of α, β-unsaturated carboxylic acid monomer,
The content of the α, β-unsaturated carboxylic acid monomer such as the other monomer component B is preferably 20% by weight or less, and the α of the monomer component A and the other monomer component B and the like is preferably. It is preferable that the contents of the .beta.-unsaturated carboxylic acid monomers are the same, because the resulting polymer has the highest transparency.

In the production method of the present invention, the above method I
In both cases II and II, it is important to control the polymerization rate. The polymerization rate can be determined by any method,
As a simpler method, there is a method using gas chromatography, and the polymerization rate can be determined by quantifying the amount of remaining monomer components. Distribution of Tg of the polymer of the invention,
That is, the shape of the differential curve obtained by measurement with DSC is determined by the balance of mechanical strength, temperature sensitivity, transparency, etc. of the polymer. In the above methods I and II, a specific method for controlling the Tg distribution of the polymer will be described below.

When a higher level of transparency is required in the polymer obtained by the production method of the present invention, the ratio of the area occupied by the peak between 20 and 40 ° C. in the differential curve is increased, that is, 10 % Or more, preferably 20% or more. For this purpose, in Method I, the monomer components B, C, D and the like may be added slowly, that is, over 1 hour, and in Method II, the monomer components A and B, C, D and the like may be added. In order to prevent the polymerization rate from becoming too large in the separate polymerization stage, ie 8
Polymerization may be performed so that the amount becomes 0% or less.

In the polymer obtained by the production method of the present invention, when the temperature sensitivity is particularly reduced, the ratio of the area occupied by the peak between 20 and 40 ° C. in the differential curve is reduced, that is, 50%. Must be: For this purpose, contrary to the case where the above transparency is required, in the method I, the monomer components B, C, D and the like may be added relatively quickly, that is, within 3 hours, and in the method II. The polymerization rate at the stage of separately polymerizing the monomer components A and B, C, D and the like may be increased, that is, the polymerization may be performed so as to be 50% or more.

In the polymer obtained by the production method of the present invention, if the tear strength, the elongation or the flexibility at low temperature is particularly required, the peak top on the low temperature side may be increased by the differential curve. For this purpose, in Method I, when the monomer component A is a monomer component that gives a polymer having a lower Tg, the polymerization rate in the polymerization of the monomer component A is high, That is, it should be 40% or more,
On the contrary, when the monomer component A is a monomer component which gives a polymer having a higher Tg, the monomer components B, C, D
Etc. may be added slowly, that is, over 1 hour. In Method II, the monomer components A and B,
The polymerization rate at the stage of separately polymerizing C, D, etc. may be increased, that is, the polymerization rate may be 50% or more.

Further, in the polymer obtained by the production method of the present invention, when tensile strength and blocking resistance are required, the peak top on the high temperature side may be increased by the differential curve. To this end, in Method I, when the monomer component A is a monomer component that gives a polymer having a higher Tg, the polymerization rate in the polymerization of the monomer component A is high, That is, it may be 40% or more. Conversely, when the monomer component A is a monomer component that gives a polymer having a lower Tg, the monomer components B, C, D, etc. are slowly added. That is, it may be added over 1 hour. Further, in Method II, the polymerization rate at the stage of separately polymerizing the monomer components A and B, C, D, etc. is increased, that is, 5
Polymerization may be performed so as to be 0% or more.

As described above, the balance of the mechanical strength, transparency, blocking resistance and temperature sensitivity of the polymer, which varies depending on the use, is controlled by controlling the polymerization rate and the mixing rate during the polymerization in the production method of the present invention. Can be designed. In the above methods I and II, if a step of further mixing a polyvalent metal salt is included, the resulting polymer is subjected to metal crosslinking, so that the resulting polymer film has mechanical strength (tensile and tear strength). In addition, the anti-blocking property is further improved, and the material has more stable strength and dimensional stability against changes in temperature or humidity. The polyvalent metal used for metal cross-linking is not particularly limited, and examples thereof include the polyvalent metal salts described above. Preferred examples of the polyvalent metal salt are also the same as those described above. Use of Polymer Having High Acid Value [Coating Agent] The coating agent of the present invention contains the above polymer and an organic solvent. Further, the coating agent may contain additives other than these as required.

Any polymer may be used as long as it is the above-mentioned polymer, but among them, a polymer containing a polyvalent metal salt makes the resulting coating more excellent in mechanical strength and blocking resistance. preferable. Specific examples of the organic solvent include alcohols such as methanol, ethanol and isopropyl alcohol; aromatic hydrocarbons such as benzene and toluene; ketones such as acetone and methyl ethyl ketone; aliphatic esters such as ethyl acetate and butyl acetate. Can be mentioned.

Examples of the additives include fillers,
A plasticizer, a lubricant, etc. can be mentioned, and these can be blended appropriately. Specific examples of the filler include kaolin, asbestos, mica and the like. The filler may be added in an arbitrary amount depending on the purpose, but is 0.1% with respect to 100 parts by weight of the polymer.
It is preferably from 10 to 10 parts by weight.

Specific examples of the plasticizer include dioctyl phthalate, tributyl acetylcitrate and the like. The compounding amount of the plasticizer is preferably 1 to 50 parts by weight with respect to 100 parts by weight of the polymer. Specific examples of the lubricant include stearyl alcohol, stearic acid, stearic acid amide, calcium stearate and the like. The blending amount of the lubricant is the polymer 1
It is preferably 0.1 to 30 parts by weight with respect to 00 parts by weight.

By applying the coating agent of the present invention to the surface of various objects, a film or coating is formed on the surface. Specific examples of various objects include films, papers (paper base materials), sheets, metal plates, concrete and the like. In particular, it is preferable to use the coating agent of the present invention for a film or a paper because not only gloss and the like are given at the time of use but also the paper or the like after use can be reused. [Film] The film of the present invention contains the polymer. Further, the film may contain a filler, a plasticizer, a colorant, a lubricant and the like, if necessary.

As the filler, plasticizer and lubricant, those described in the above coating agent can be used as they are. The same applies to the preferable blending amount. Specific examples of the colorant include various pigments such as aluminum, titanium oxide, zinc oxide, yellow lead, ultramarine blue and carbon black, and various dyes such as azo dyes, anthraquinone dyes and phthalocyanine dyes. The amount of the colorant compounded is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the polymer.

The film of the present invention may be produced by a) a method of using the above coating agent to evaporate the solvent contained in the coating agent at room temperature or under heating, that is, a so-called casting method. ) The polymer may be molded into a sheet to be manufactured. In the method using a coating agent, the film thickness of the film is preferably uniform in order to keep the mechanical strength of the obtained film constant. A commonly used coating machine such as a roll coater, a reverse coater, a gravure coater, or a bar coater is used to keep the film thickness uniform. The film can be produced by applying the coating agent onto the surface of paper, film or the like using the coating machine and then evaporating the solvent contained in the coating agent. here,
When the surface of the paper, film or the like coated with the coating agent has releasability, the surface can be separated from the film, and a single film can be obtained. Also,
When the surface of paper, film or the like has no peeling property and the surface and the film are in close contact with each other, a laminated film and paper laminated with the film, that is, processed paper can be obtained.

In the method of molding the polymer, for example, the polymer is melt-extruded by an extruder, T-
The film can be produced by an extrusion molding method such as die molding, inflation molding, blow molding, or laminate molding, or a calendering method. If necessary, the obtained film may be further uniaxially or biaxially stretched.

The thickness of the film is not particularly limited, but is usually 10 to 200 μm. From the viewpoint of film strength and moldability, it is preferably 30 to 100 μm. The film of the present invention is printable, has little strength change due to temperature change, is hard to block at high temperature, has high flexibility at low temperature, has high tensile strength and tear strength, is resistant to whitening even when pulled, and is water-soluble and / or Alternatively, since it is alkali-soluble and has excellent transparency, it is used in various applications described in detail below. [Packaging Bag] The packaging bag of the present invention comprises the film.

In order to use it as a packaging bag, it must have excellent heat-sealing properties, elongation, tensile strength and tear strength. As a method of manufacturing the packaging bag, the film obtained by molding by various molding methods is further heat-sealed to obtain the packaging bag. As the molding method, inflation molding is the most simple and preferable.

The size of the packaging bag is not particularly limited and can be freely set according to its use. Since the packaging bag thus obtained is water-soluble and / or alkali-soluble, it can be used as an individual packaging bag for pesticides, detergents, etc., or as a laundry bag. It is possible to save the trouble of taking out the contents of and to prevent chemical damage. [Adhesive (Adhesive) Adhesive Sheet] The adhesive (adhesive) adhesive sheet of the present invention comprises the film and an adhesive (adhesive) adhesive. As the adhesive (adhesive) sheet, a sheet including the film and a layer made of an adhesive (adhesive) adhesive formed on the surface of the film is preferable because the adhesive (adhesive) property is high. The layer made of adhesive (adhesive) is
It may be formed on one side or both sides of the film. Further, the layer composed of the adhesive (adhesive) may be formed on one surface or the entire surface of the film,
It may be formed on one surface or a part of the entire surface of the film.

The adhesive (adhesive) adhesive sheet can be used for all purposes of sticking a film or sheet to an adherend, and as an adhesive (adhesive) adhesive tape or the like, for example, as a label for glass or the like. Used. The surface of the label may be printed. In this case, the film needs to have a tensile strength sufficient to withstand the tension at the time of printing, and therefore the film has a uniform thickness and is preferably 30 μm or more. The printing may be performed on any surface of the film, but it is preferable that the printing is performed on the back surface, that is, on the side of the adhesive (adhesive) because of high weather resistance.

As a method for producing the film used for the adhesive (adhesive) sheet, T-die extrusion molding, casting method and the like are preferable. As the adhesive (adhesive), for example,
Natural rubber-based adhesive (adhesive), SIS and SBR-based synthetic rubber adhesive (adhesive), acrylic adhesive (adhesive), silicone adhesive, vinyl acetate adhesive (adhesive) Adhesive, polyvinyl alcohol-based adhesive (adhesive), EVA-based adhesive (adhesive),
Examples thereof include urethane-based adhesive (adhesive) and acrylic-based alkali-soluble adhesive (adhesive). Above all, it is preferable that the adhesive (adhesive) is an alkali-soluble alkali-soluble adhesive (adhesive) because the entire sheet can be dissolved and completely removed.

The method for producing the adhesive (adhesive) sheet is not particularly limited. For example, the adhesive (adhesive) adhesive is applied as it is by a general coating machine such as a hot melt coater, a rivus coater, a gravure coater, a bar coater. And then dried. The adhesive (adhesive) sheet thus obtained is used, for example, for labels for bottles and paper products, and can be easily removed by alkali treatment after use.

The method of printing on the above-mentioned film is not particularly limited, and any method can be used for printing. As the printing ink used for printing, for example,
Letterpress ink, planographic ink, gravure ink, flexo ink, screen ink, intaglio ink, thermal transfer ink,
Examples thereof include resist ink. [Window Opening Envelope] The window opening envelope of the present invention includes an envelope main body having a window and the film closing the window.

The material constituting the envelope body is not particularly limited as long as it is a material normally used for envelopes.
It is a paper base material described later and may be polypropylene or the like. In order to make the contents put in the envelope and the address etc. written on the contents visible from the outside,
The envelope body has a window. The film that closes the window of the envelope body may be a film obtained by the same manufacturing method as the film used for the pressure-sensitive adhesive (adhesive) sheet, or may have the surface of the film printed.

The method for manufacturing the windowed envelope is not particularly limited, but, for example, the periphery of the window portion of the envelope body is adhered to the film by using the above-mentioned adhesive (adhesive) adhesive to form the envelope body. There is a method of closing the window part of the.
It is also possible to weld the film and the periphery of the window portion of the envelope body by heating or the like without using the adhesive (adhesive), and close the window portion of the envelope body with the film. In the windowed envelope thus obtained, the film can be easily removed by alkali treatment after use, and it becomes easy to collect and utilize the material constituting the envelope body such as the paper base material. [Recyclable Processed Paper] The reproducible processed paper of the present invention includes a paper base material and the above-mentioned film laminated on the paper base material.

There is no particular limitation on the paper base material constituting the recyclable processed paper, and for example, a paper base material made of plain paper, high-quality paper, kraft paper, glassine paper or the like is used. The thickness of the film is not particularly limited, but 10 to 100
It is preferably μm. There is no particular limitation on the method for producing the reusable processed paper, which can be obtained by laminating a film and a paper substrate. For example, a) the coating agent of the present invention can be applied to a coating machine such as a roll coater or a gravure coater. A method of evaporating a solvent after coating or impregnating a paper base material using the method, b) devolatilizing the coating agent of the present invention and subjecting the polymer composition to T-die extrusion molding and at the same time paper base There is a method of laminating the material.

The renewable processed paper of the present invention is non-blocking and has little deformation, and the laminated film can be easily removed by stirring in neutral water or alkaline water such as a 1% sodium hydroxide aqueous solution. Since the paper base material disaggregates, it can be recycled. In addition, a reproducible paper label base material is obtained by printing on the film of the recyclable processed paper.

The printing method is not particularly limited, and any method can be used for printing. Examples of the printing ink used for printing include letterpress ink, planographic ink, gravure ink, flexo ink, screen ink, intaglio ink, thermal transfer ink, resist ink and the like. Similar to renewable processed paper, the renewable paper label substrate is non-blocking and has little deformation, and when laminated in neutral water or alkaline water, for example, 1% sodium hydroxide aqueous solution, a laminated film can be easily formed. The paper base is disintegrated and disintegrated so that it can be recycled. [Renewable Release Paper] The releasable release paper of the present invention includes a paper base material, the above-mentioned film laminated on the paper base material, and a release agent layer laminated on the film. That is, the releasable release paper is a film that the recyclable processed paper has and further includes a release agent layer.

Examples of the release agent include silicone resin, fluororesin, acrylic resin and the like. As a method for laminating the release agent layer on the recyclable processed paper, for example, there is a method in which the release agent is dispersed in an organic solvent such as toluene, coated, and dried. The thickness of the release agent layer is not particularly limited, but is preferably 0.5 to 5 μm, for example, since a release agent layer having sufficient release ability and fixability can be obtained by one coating. [Laminated film] The film of the present invention, polyvinyl alcohol, polyethylene oxide, water-soluble resin film such as polydioxolane, polyolefin, polyester,
It can be laminated on a hydrophobic resin such as a fluororesin.

The laminated film and the processed paper thus obtained are not only provided with surface properties such as strength, gloss, adhesiveness, printability, etc., but also coated with a neutral or alkaline water. It is very useful because it can be reused by processing.

[0074]

The following examples are illustrative of the invention and are not intended to limit the scope of the claims of the invention. In the following Examples and Comparative Examples, "parts" and "%" represent "parts by weight" and "% by weight", respectively. -Example 1-In a 50 L tank type reactor, ethyl acrylate 2.4 k
g, acrylic acid 0.45 kg, methyl methacrylate 0.
Monomer component A consisting of 15 kg of methanol, 3 kg of methanol and 12 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (calculated T of the polymer given by the monomer component A)
g was −6 ° C.), heated to 65 ° C. in a nitrogen atmosphere and reacted for 20 minutes to carry out polymerization until the polymerization rate reached 72%. Continuously, 2.1 kg of methyl acrylate, 1.05 kg of acrylic acid, 3.85 kg of methyl methacrylate,
7 kg of methanol and 2,2'-azobis (2,4-
Dimethyl valeronitrile) 28 g monomer component B
(The calculated Tg of the polymer obtained by the monomer component B is 70.
(.Degree. C.) was uniformly added dropwise over 2 hours, and then polymerization was carried out at 65.degree. After the dropping was completed, the polymerization for aging was continued at 65 ° C. for 2 hours. As a result, the number average molecular weight was 92,000, and the differential curve obtained by measurement with the DSC shown in FIG.
Low temperature (14.4 ° C, 93μW / min, full width at half maximum a: 1
2.1 ° C side peak top and high temperature (57.9 ° C, 24
A coating agent (1) containing a polymer having a height ratio to the peak top on the side of 7 μW / min, full width at half maximum a: 12.9 ° C. of about 1: 3 was obtained.

The coating agent (1) thus obtained was devolatilized under reduced pressure heating using a twin-screw extruder to give 20% of the resulting composition.
A film was obtained by T-die molding at 0 ° C. Using this film as a label substrate, measurement by DSC, mechanical strength, etc. were measured by the following methods. Table 1 shows the results.
Further, a pressure-sensitive adhesive solution synthesized by the following method was applied to release paper and dried to form a pressure-sensitive adhesive layer having a thickness of 25 μm, and the film having a thickness of 60 μm obtained in Example 1 was pressure-bonded thereto, An adhesive sheet having an adhesive layer formed on one side was obtained. The alkali removability when this adhesive sheet was used as a label was evaluated by the following method. Table 1 shows the results.

A film having a size slightly larger than the window of the envelope body is prepared, and the adhesive is applied only to the peripheral edges of this film in the same manner as the above-mentioned pressure-sensitive adhesive sheet. A window-opened envelope was produced by sticking it to the window. The obtained window-opened envelope was subjected to an alkali beating test, and the recoverability as waste paper was evaluated. Table 1 shows the results. Synthesis of adhesive solution 0.8 kg of butyl acrylate, 0.2 kg of acrylic acid,
3 g of 2,2′-azobisisobutyronitrile and 1 kg of ethyl acetate were charged into a tank reactor having a volume of 5 L, and heated at 80 ° C. under a nitrogen atmosphere to carry out polymerization for 2 hours. 200 g of polyethylene glycol having a weight average molecular weight of 1000 was added to the obtained polymerization solution to obtain a pressure-sensitive adhesive solution. Measurement with DSC : 10 m with DSC220C manufactured by Seiko Instruments Inc.
D obtained by measuring in a nitrogen atmosphere using a sample of g
The SC curve and differential curve are shown in FIG. The measurement conditions are as follows: first raise the temperature to 150 ° C, hold for 5 minutes, and then
It was rapidly cooled to -100 ° C and held for 5 minutes. Further 15
0 ° C up to 10 ° C / min. The temperature was raised at and a differential curve was obtained. A base line was drawn by connecting the points where the differential value was 0 μW / min. The ratio of the height of the peak top on the low temperature side to the peak top on the high temperature side from the baseline is 1: 3.
Is recognized. Tensile strength, elongation and temperature sensitivity Tested according to JIS K7127.

Under the condition 1, in the atmosphere of 23 ° C. and 55% RH, the thickness of the film used for the test was 50 μm, and the test speed was 200 mm / min. Met. 10 in condition 2
C., 55% RH, under the condition 3, tensile strength was measured in the same manner as in the condition 1 except that the measurement was performed under the atmosphere of 40.degree. C., 55% RH, and the temperature sensitivity was evaluated. Tear strength Tested according to JIS K7128. The thickness of the film used in the test is 50 μm, and the test speed is 200 mm /
min. Met. Transparency Using a test piece having a thickness of 65 μm, a parallel light transmittance measured by irradiating visible light in the thickness direction with a turbidimeter ND-1001DP manufactured by Nippon Denshoku Industries Co., Ltd. was used for evaluation. The appearance at the time of measuring the tensile strength under the whitening condition 1 was observed and evaluated. The evaluation criteria are as follows.

◯: Whitening did not occur until just before breaking. Δ: Whitening occurred before the elongation reached 150%. X: Whitening occurred until the elongation reached 100%. The rate of dimensional change after leaving for 72 hours in an atmosphere of shrinkage of 30 ° C. and 80% RH was measured. Blocking property The coiled film was left at 50 ° C. to evaluate the degree of blocking. The evaluation criteria are as follows.

⊚: Rewinding was easy. ○: There was some resistance to rewinding. Δ: There were places where the film could not be rewound. X: Rewinding was not possible at all. Acid value Hiranuma Sangyo Co., Ltd. automatic titrator (COMTE-98
0) was used to determine a solution of 1 g of the film dissolved in 100 g of methanol by titration with a 0.1 N aqueous sodium hydroxide solution. Alkali-removable form: Wrap the film around the bottle once, heat seal it, and stick it on the bottle as a label, 25 ° C, 0.4
% Of sodium hydroxide aqueous solution, the time required for dissolution and removal was measured.

Form: 10 cm × 10 with release paper laminated
A test piece made of a pressure-sensitive adhesive sheet having a size of cm was prepared, the release paper and the pressure-sensitive adhesive sheet were peeled off, and the pressure-sensitive adhesive sheet was attached to a beer bottle (7 cm in diameter) as a label. The labeled beer bottle was immersed in 5 liters of 0.4% sodium hydroxide aqueous solution at 25 ° C. and stirred, and the time required until the label was dissolved and removed was measured. Beating test for windowed envelopes A 5 cm × 5 cm window is opened in a 12 cm × 26 cm envelope, and the pressure-sensitive adhesive solution described above is used in this window part to form a 5.5 cm
A film with a size of 5.5 cm was attached from the inside of the envelope to produce a windowed envelope. The obtained window-opened envelope is 70
The state of the film was observed by immersing it in a 3% sodium hydroxide aqueous solution at 3 ° C and vigorously stirring, and evaluated according to the following evaluation criteria.

A: Completely beaten Δ: A small piece of film or paper remained. X: The film remained as it was. Soluble film 10g in neutral and acidic water is immersed in ion-exchanged water and 0.1N hydrochloric acid for 24 hours, then dried, the weight loss rate is measured, and the elution amount (%) is determined to obtain water resistance. The sex was evaluated. The printed image was subjected to offset printing with a RI-1 type printing tester, and its appearance (deviation, wrinkle, bleeding degree) was observed and evaluated.
The evaluation criteria are as follows.

⊚: Very good ∘: Good Δ: Somewhat bad ×: Poor ink fixing property F-Gloss manufactured by Dainippon Ink and Chemicals, Inc.
Offset printing was performed with a RI-1 type printing tester, and 10 minutes after printing, fine papers were overlaid and pressed, and the density of the ink transferred to the fine papers was observed and evaluated. The evaluation criteria are as follows.

◯: No transfer occurred. Δ: Slightly transferred. X: Transferred in large quantities. -Example 2- In Example 1, the polymerization time of the monomer component A was set to 10 minutes, and the monomer component B was polymerized until the polymerization rate reached 40%.
Polymerization was carried out with the same composition and method as in Example 1 except that was added dropwise. As a result, the number average molecular weight was 98,000, and D
The differential curve obtained by measuring with SC shows low temperature (14.1
A coating agent (2) containing a polymer having a height ratio of the peak top on the (° C.) side to the peak top on the high temperature (52.3 ° C.) side of about 1: 9 was obtained.

The obtained coating agent (2) was used in Example 1
In the same manner as above, the film was obtained by devolatilization with a twin-screw extruder and T-die molding at 210 ° C. The film was used as a label substrate, a pressure-sensitive adhesive sheet and a windowed envelope to evaluate mechanical strength and the like in the same manner as in Example 1, and the results are shown in Table 1. Example 3 To the coating agent (1) obtained in Example 1, 400 g of calcium stearate in toluene was added and stirred to be uniform, and further heated to 60 ° C. and stirred for 30 minutes for coating. Agent (3) was obtained. The coating agent (3) thus obtained was devolatilized with a twin-screw extruder in the same manner as in Example 1 and subjected to T-die molding at 200 ° C to obtain a film. Using this film as a label base material, an adhesive sheet and a windowed envelope, mechanical strength and the like were evaluated in the same manner as in Example 1,
The results are shown in Table 1.

-Comparative Example 1- The monomer component obtained by mixing the monomer components A and B of Example 1 was heated to 65 ° C in a nitrogen atmosphere in a tank reactor having a capacity of 50 L for 2 hours. Collective polymerization was performed to obtain a comparative coating agent (1) containing a polymer having a number average molecular weight of 103,000 and a Tg of 39 ° C. In the same manner as in Example 1, the comparative coating agent (1) was devolatilized with a twin-screw extruder to give 220
A film was obtained by T-die molding at ℃. The film was used as a label substrate, a pressure-sensitive adhesive sheet and a window-opened envelope to evaluate mechanical strength and the like in the same manner as in Example 1, and the results are shown in Table 1.
Shown in

Comparative Example 2-Monomer component A of Example 1 for comparison with the mixture
And B were individually heated to 65 ° C. in a nitrogen atmosphere and polymerized to a polymerization rate of 95% or more over 2 hours. From the monomer component A, the number average molecular weight is 121,000 and the Tg is 13
A solution containing the polymer at ° C was obtained. Further, a solution containing a polymer having a number average molecular weight of 82,000 and a Tg of 65 ° C. was obtained from the monomer component B. By mixing the solution containing the obtained polymer,
Comparative coating agent (2) was obtained. In the same manner as in Example 1, the comparative coating agent (2) was devolatilized with a twin-screw extruder,
A film was obtained by T-die molding at 220 ° C. The film was used as a label substrate, a pressure-sensitive adhesive sheet and a windowed envelope to evaluate mechanical strength and the like in the same manner as in Example 1, and the results are shown in Table 1.

-Comparative Example 3-For comparison with an emulsion polymer, a tank reactor having a capacity of 50 L was charged with 2.4 kg of ethyl acrylate and 0.
45 kg, methyl methacrylate 0.15 kg, water 3 k
g, 45 g of sodium lauryl sulfate, 7.5 g of ammonium persulfate and 90 g of bromotrichloroethane were charged, and the mixture was heated to 80 ° C. in a nitrogen atmosphere until polymerization reached 69%. Continuously, polymerization was carried out at 80 ° C. in a nitrogen atmosphere to a polymerization rate of 69%, and then 2.1 kg of methyl acrylate and 1.
05kg, methyl methacrylate 3.85kg, water 7k
g, sodium lauryl sulfate 105 g, ammonium persulfate 17.5 g and bromotrichloroethane 210 g
Comparative monomer component B consisting of was uniformly added dropwise over 2 hours, and then polymerization was carried out at 80 ° C. After the dropping was completed, the polymerization for aging was continued at 80 ° C. for 2 hours. Obtained comparative coating agent consisting of a polymer emulsion (3)
Was cast into a film. The film was used as a label substrate, a pressure-sensitive adhesive sheet and a windowed envelope to evaluate mechanical strength and the like in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 4 In order to make a comparison with a polymer having a low acid value, a tank reactor having a capacity of 50 L was charged with 2.4 kg of ethyl acrylate, 0.15 kg of acrylic acid and 0.45 kg of methyl methacrylate. , 3 kg of methanol and 12 g of 2,2′-azobis (2,4-dimethylvaleronitrile) were charged, and the mixture was heated to 65 ° C. under a nitrogen atmosphere until the polymerization rate reached 68%. Polymerization was carried out for a minute. Subsequently, comparative monomer component D consisting of 2.1 kg of methyl acrylate, 0.35 kg of acrylic acid, 4.55 kg of methyl methacrylate, 7 kg of methanol and 28 g of 2,2′-azobis (2,4-dimethylvaleronitrile). Was uniformly added dropwise over 2 hours and a half, and polymerization was subsequently carried out at 65 ° C. After the dropping was completed, the polymerization for aging was continued at 65 ° C. for 2 hours. As a result, a comparative coating agent (4) containing a polymer having a number average molecular weight of 81,000 was obtained. This comparative coating agent (4) was devolatilized with a twin-screw extruder in the same manner as in Example 1 and subjected to T-die molding at 190 ° C to obtain a film. Using this film as a label base material, an adhesive sheet and a windowed envelope, mechanical strength and the like were evaluated in the same manner as in Example 1,
The results are shown in Table 1.

Comparative Example 5 A comparative pressure-sensitive adhesive sheet (5) was prepared in the same manner as in Example 1 by using a commercially available polyethylene terephthalate (PET) film (thickness: 50 μm) and the pressure-sensitive adhesive solution obtained in Example 1. )
Was produced and evaluated as a label. A window-opened envelope was prepared in the same manner as described above, this was also evaluated, and the results are shown in Table 1.
Shown in

[0090]

[Table 1]

From Table 1, it can be seen that the films shown in Examples 1 to 3 are excellent in mechanical strength and dimensional characteristics, do not cause blocking, and have good printability, and are satisfactory as a label substrate. Further, the strength change due to temperature is smaller than that of the batch polymer of Comparative Example 1, and the tear strength and elongation are large as compared with the blend of Comparative Example 2 and the emulsion polymer of Comparative Example 3 to improve transparency. Is also excellent. Further, it has a feature that it is superior in water resistance as compared with the emulsion polymer. Further, the labels of the examples are Comparative Examples 2, 4 and 5.
It is very useful because it can be easily removed by alkaline treatment after use, unlike the label of No. 1.

Further, as seen from the results of Examples 1 and 2, the mechanical strength and the like can be freely designed by changing the ratio of peak tops. -Example 4-In a tank reactor having a volume of 50 L, 1.8 k of methyl acrylate was added.
g, acrylic acid 0.61 kg, methyl methacrylate 1.
Monomer component C consisting of 6 kg, 5 kg of methanol and 32 g of 2,2'-azobis (2,4-dimethylvaleronitrile) (calculated T of the polymer given by the monomer component C
(g is 55 ° C.), and the mixture was heated to 65 ° C. in a nitrogen atmosphere and polymerized for 45 minutes until the polymerization rate reached 73%. Continuously, 2.3 kg of ethyl acrylate, 0.4 of acrylic acid
kg, 3.3 kg of methanol and 22 g of 2,2'-azobis (2,4-dimethylvaleronitrile), a monomer component D (calculated T of the polymer given by the monomer component D).
(g: -11 ° C) was uniformly added dropwise over one and a half hours, and then polymerization was performed at 65 ° C. After the dropping is completed, the temperature is further increased to 65 ° C for 2
Polymerization for aging was continued. As a result, the number average molecular weight was 72,000, and the low temperature side (18.7 ° C) and the high temperature side (5
A coating agent (4) containing a polymer having a peak top ratio (3.1 ° C.) of 1: 1 was obtained. The coating agent (4) was devolatilized with a twin-screw extruder in the same manner as in Example 1 to obtain 180
Inflation molding was performed at 0 ° C. to obtain a bag-shaped film.
Using this film as a packaging bag, mechanical strength and the like were evaluated by the same method as in Example 1 and the following method, and the results are shown in Table 2. Solubility in Detergent Aqueous Solution and Water The time until the film was dissolved was measured by immersing the film in a detergent aqueous solution at 50 ° C. in which 5 g of a powder detergent (Attack, manufactured by Kao Corporation) was dissolved in 1 liter of tap water, and the time was measured. Further, the same test was conducted only on tap water. 20 heat-sealable films (size: 5 cm x 5 cm)
After heat-sealing with a heat sealer at 0 ° C. for 1 second, the force required for peeling was measured.

Example 5 A tank reactor having a capacity of 50 L was charged with 1.8 k of methyl acrylate.
g, acrylic acid 1.53 kg, methyl methacrylate 0.
A monomer component E consisting of 68 kg, 5 kg of methanol and 32 g of 2,2'-azobis (2,4-dimethylvaleronitrile) (calculated T of the polymer given by the monomer component E)
(g is 55 ° C.), and the mixture was heated to 60 ° C. in a nitrogen atmosphere and polymerized for 30 minutes until the polymerization rate reached 78%. Sequentially, butyl acrylate 0.5 kg, ethyl acrylate 1.2 kg, acrylic acid 1.0 kg, methanol 3.3.
kg and 2,2'-azobis (2,4-dimethylvaleronitrile) 22g monomer component F (the calculated Tg of the polymer of the monomer component F is 4 ° C) is divided into 10 equal parts. It was charged in portions every 10 minutes, and polymerization was subsequently carried out at 60 ° C. After completion of the dropping, polymerization for aging was continued at 60 ° C. for 2 hours. As a result, a coating agent (5) containing a polymer having a number average molecular weight of 95,000 and a peak top ratio on the low temperature side (18.1 ° C) and the high temperature side (58.6 ° C) of 1: 1 was obtained. Was obtained. After adding 268 g of stearic acid amide to the coating agent (5), this was devolatilized by a twin-screw extruder in the same manner as in Example 4 and inflation-molded at 200 ° C., and the obtained film was used as a packaging bag in Example 4 The mechanical strength and the like were evaluated in the same manner as in, and the results are shown in Table 2.

-Example 6- Two tank reactors having a capacity of 50 L were prepared, each containing 2.1 kg of methyl acrylate and 1.05 kg of acrylic acid.
A monomer component G composed of 3.85 kg of methyl methacrylate, 7 kg of methanol and 56 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (the calculated Tg of the polymer obtained by the monomer component G is 55). C.) and 2.55 kg of ethyl acrylate, 0.45 kg of acrylic acid, 3 kg of methanol and 24 g of 2,2'-azobis (2,4-dimethylvaleronitrile) 24 g (monomer component H is (The calculated Tg of the polymer to be given is −11 ° C.), and each was individually heated to 65 ° C. in a nitrogen atmosphere, and polymerization was performed for 1 hour until the respective polymerization rates reached 58% and 78%. . Continuously, the contents of the tank reactor in which the monomer component H was polymerized were dropped evenly over 1 hour from the tank reactor in which the monomer component H was polymerized,
Then, polymerization was carried out at 65 ° C. 65 ° C after the dropping
The polymerization for aging was continued for 1 hour. As a result, the number average molecular weight was 75,000, and the peak on the low temperature side (10.2 ° C)
A coating agent (6) containing a polymer in which the peak ratio of the high temperature side peak (57.1 ° C.) was 4: 6 was obtained. The coating agent (6) was devolatilized by a twin-screw extruder in the same manner as in Example 4, and inflation-molded at 190 ° C, and the obtained bag-shaped film was used as a packaging bag in the same manner as in Example 4 to obtain mechanical strength. Etc. were evaluated and the results are shown in Table 2.

Comparative Example 6 The monomer components C and D of Example 4 were individually heated to 65 ° C. in a nitrogen atmosphere and polymerized to a polymerization rate of 95% or more over 2 hours. A solution containing a polymer having a number average molecular weight of 670000 and a Tg of 51.3 ° C. was obtained from the monomer component C, and a solution having a number average molecular weight of 79,000 and a Tg was obtained from the monomer component D.
A solution containing a polymer having a temperature of 10.8 ° C. was obtained. The solution containing the obtained polymer was mixed to obtain a comparative coating agent (5). In the same manner as in Example 4, the comparative coating agent (5) was devolatilized with a twin-screw extruder and inflation-molded at 180 ° C, and the obtained bag-shaped film was used as a packaging bag in the same manner as in Example 4. The mechanical strength and the like were evaluated, and the results are shown in Table 2.

-Comparative Example 7-Using the film obtained in Comparative Example 4 as a packaging bag, Example 4
The mechanical strength and the like were evaluated in the same manner as in, and the results are shown in Table 2.

[0097]

[Table 2]

From Table 2, the packaging bags of Examples 4 to 6 have strength,
The transparency and heat sealability are sufficient, there is no whitening, and it is perfect as a packaging bag. Furthermore, the packaging bag of Example 5 which has alkali solubility and has a particularly high acid value is also water-soluble. -Example 7-The coating agent (1) obtained in Example 1 was coated on a plain paper having a thickness of 50 μm using a bar coater and then dried, and an alkali-soluble film layer having a thickness of 10 μm was formed on the plain paper. A recyclable processed paper on which the above was formed was obtained. FIG. 2 shows a cross-sectional view of this recyclable processed paper. Recyclable processed paper 6 has an alkali-soluble film layer 4 laminated on plain paper 5.

The physical properties of the obtained processed paper were measured by the following methods, and the results are shown in Table 3. 2 sheets of blocking processed paper (size: 5cm x 5cm) are stacked and 1k
A load of gf / cm ² was applied and the mixture was left at room temperature to evaluate the degree of blocking. The evaluation criteria are as follows.

◯: Peeling is easy. Δ: There is some resistance to peeling. X: Peeling is difficult. Curled paper (size: 5 cm x 5 cm) at 30 ° C, 80% R
It was left in a thermo-hygrostat of H for 5 hours and then dried, and its appearance was observed and evaluated. The disaggregated processed paper (size: 5 cm × 5 cm) was immersed in 1 liter of a 0.1% aqueous sodium hydroxide solution and stirred with a mixer, and then the presence or absence of undisaggregated substances was observed and evaluated.

◯: Completely disaggregated. Δ: Partly disaggregated. X: No disaggregation was observed. -Comparative Examples 8 and 9- Comparative coating agents (1) obtained in Comparative Examples 1 and 4.
In the same manner as in Example 7, (4) and (4) were coated on plain paper and then dried to obtain processed paper.

Physical properties of the obtained processed paper were measured in the same manner as in Example 7, and the results are shown in Table 3. -Example 8-The alkali-soluble film layer of the processed paper obtained in Example 7 is coated with a solution in which a silicone resin is dispersed in toluene using a bar coater, and then dried to form a release layer having a thickness of 1 µm. Thus, a releasable release paper on which was formed was obtained. FIG. 3 shows a cross-sectional view of this release paper. The releasable release paper 8 has the alkali-soluble film layer 4 laminated on the plain paper 5, and the silicone resin layer 7 laminated on the alkali-soluble film layer 4.
have. Physical properties of the obtained releasable release paper were measured in the same manner as in Example 7, and the results are shown in Table 3.

[0103]

[Table 3]

From Table 3, the recyclable processed paper and the releasable release paper obtained by using the coating agents of Examples 7 and 8 are excellent in the dimensional stability of the resin, and thus are hard to curl and are non-blocking. It is easy to disintegrate by alkali treatment.

[0105]

The polymer of the present invention is a polymer having an acid value of 70 mgKOH / g or more obtained by polymerizing an α, β-unsaturated carboxylic acid monomer and a vinyl monomer. The differential curve obtained by measurement with a differential scanning calorimeter is -80 to 120.
Since it has two or more peak tops between 0 ° C and a parallel light transmittance of 70% or more, there is little change in physical properties due to temperature changes, and it has water solubility and / or alkali solubility,
Excellent transparency.

The differential curve is between −30 and 20 ° C.
Having a peak top at each of 40 to 100 ° C.,
When the parallel light transmittance is 80% or more, the polymer is
It becomes more transparent, has high flexibility at low temperature, has high tear strength, strong tensile strength and elasticity, and does not cause blocking. 30% by weight or more of the vinyl-based monomer is an acrylic acid alkyl ester and / or a methacrylic acid alkyl ester, and in a polymer obtained by polymerizing in a non-aqueous system, when the obtained polymer is a film, flexibility, The toughness, gloss, weather resistance and transparency are improved, the structure is uniform, the transparency is high, whitening is difficult, and the strength is sufficient.

When the α, β-unsaturated carboxylic acid monomer is acrylic acid and / or methacrylic acid,
The structural unit of the β-unsaturated carboxylic acid monomer is 9 in the polymer.
When it is at least wt%, flexibility and toughness are improved, and the polymer has a good balance of solubility, water resistance and flexibility. When the polyvalent metal salt is further contained, mechanical strength is further increased, blocking is less likely to occur, and more stable strength and dimensional stability against temperature and humidity changes are obtained.

Since the coating agent of the present invention contains the above polymer and an organic solvent, it can be printed, hardly blocks at high temperature, has high flexibility at low temperature, and has water solubility and / or
Alternatively, a coating layer which is alkali-soluble and has excellent transparency and gloss can be formed. Since the film of the present invention contains the polymer, and the packaging bag and the adhesive (adhesive) adhesive sheet of the present invention are provided with the film, they are printable, have little strength change due to temperature change, are hard to block at high temperature, and have low temperature. High flexibility, high tensile strength and tear strength, hardly whitening even when pulled, water-soluble and / or alkali-soluble, and excellent in transparency.

Since the windowed envelope of the present invention comprises the above-mentioned film, it is printable, has little strength change due to temperature change, is hard to block at high temperature, has high flexibility at low temperature, and has high tensile strength and tear strength. It is difficult to whiten when pulled, is water-soluble and / or alkali-soluble, has excellent transparency, and can be easily recovered and used as waste paper.

Since the recyclable processed paper and the releasable release paper of the present invention have the above-mentioned film layer, they are printable, difficult to block at high temperature, highly flexible at low temperature, water-soluble and / or alkali-soluble, and Excellent transparency and gloss. The method for producing the polymer of the present invention comprises at least 9
A plurality of monomer components consisting of at least wt% α, β-unsaturated carboxylic acid monomer and at least one other vinyl monomer (provided that each monomer component has a different glass transition temperature). To give a polymer) by a non-aqueous polymerization using a multi-step polymerization process.
A step of polymerizing a part of one monomer component A, and a step of polymerizing the rest of the monomer component A and another monomer component while sequentially changing the compounding ratio in the polymerization system. Therefore, it is printable, has little change in strength due to temperature changes, is hard to block at high temperatures, has high flexibility at low temperatures, has high tensile strength and tear strength, and is difficult to whiten when pulled,
Having water solubility or alkali solubility, excellent transparency,
The polymer can be easily and efficiently produced.

As a method of successively changing the compounding ratio,
The monomer component A is further non-aqueous polymerized to a polymerization rate of 20 to 80% while the other monomer components are added dropwise or dividedly, so that the production can be performed more easily and efficiently. By further including the step of mixing a polyvalent metal salt, the resulting polymer film has higher mechanical strength (tensile and tear strength) and blocking resistance, and a more stable strength and resistance against changes in temperature or humidity. Being dimensionally stable.

[Brief description of drawings]

FIG. 1 is a DSC curve and differential curve diagram obtained by measuring the polymer obtained in Example 1 with a differential scanning calorimeter.

FIG. 2 is a sectional view of a recyclable processed paper obtained in Example 7.

FIG. 3 is a cross-sectional view of the releasable release paper obtained in Example 8.

[Explanation of symbols]

 1 DSC curve 2 DSC differential curve 3 Baseline 4 Alkali-soluble film layer 5 Plain paper 6 Recyclable processed paper 7 Silicone resin layer 8 Recyclable release paper

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location B32B 27/30 B32B 27/30 A C08F 220/18 MMB C08F 220/18 MMB C08J 5/18 CEY C08J 5/18 CEY C09D 133/06 PFX C09D 133/06 PFX C09J 7/02 JHR C09J 7/02 JHR

Claims (15)

[Claims] 1. An acid value obtained by polymerizing an α, β-unsaturated carboxylic acid monomer and a vinyl monomer is 70 mgKOH /
It is a polymer of g or more, and the differential curve obtained by measurement with a differential scanning calorimeter is -80 to
A polymer having two or more peak tops at 120 ° C. and a parallel light transmittance of 70% or more. 2. The differential curve is between −30 and 20 ° C.,
Having a peak top at each of 40 to 100 ° C.,
The polymer according to claim 1, wherein the parallel light transmittance is 80% or more. 3. 30% by weight or more of the vinyl-based monomer is an acrylic acid alkyl ester and / or a methacrylic acid alkyl ester, which is obtained by polymerization in a non-aqueous system.
The polymer according to claim 1 or 2. 4. The α, β-unsaturated carboxylic acid monomer is acrylic acid and / or methacrylic acid,
The structural unit of the β-unsaturated carboxylic acid monomer is 9 in the polymer.
The polymer according to any one of claims 1 to 3, which is at least wt%. 5. The polymer according to claim 1, further comprising a polyvalent metal salt. 6. A coating agent containing the polymer according to claim 1 and an organic solvent. 7. A film containing the polymer according to claim 1. 8. A packaging bag made of the film according to claim 7. 9. A pressure-sensitive adhesive sheet comprising the film according to claim 7 and a pressure-sensitive adhesive agent. 10. A window-opening envelope comprising an envelope main body having a window portion, and the film according to claim 7, which closes the window portion. 11. A paper base material, the film according to claim 7 laminated on the paper base material,
Recyclable processed paper with. 12. A recyclable release paper comprising a paper base material, the film according to claim 7 laminated on the paper base material, and a release agent layer laminated on the film. 13. A plurality of monomer components comprising at least 9% by weight or more of an α, β-unsaturated carboxylic acid monomer and one or more other vinyl-based monomers (provided that each monomer is used). The components give polymers with different glass transition temperatures),
A method for producing a polymer in which non-aqueous polymerization is performed using a multi-step polymerization process, comprising a step of polymerizing a part of at least one monomer component A, the rest of the monomer component A and another monomer. A method for producing a polymer, which comprises polymerizing a monomer component in a polymerization system while sequentially changing a compounding ratio. 14. A method of successively changing the compounding ratio is further carried out while non-aqueous polymerization of the monomer component A to a polymerization rate of 20 to 80% while dropping or dividingly adding other monomer components. The method for producing a polymer according to claim 13. 15. The method for producing a polymer according to claim 13, further comprising a step of mixing a polyvalent metal salt.