JP2014118503A - Solvent-free adhesive composition and laminate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solventless adhesive composition excellent in transparency, which can obtain a good coating appearance even when various plastic films are bonded to a metal vapor-deposited film or a metal foil and has satisfactory adhesion performance.
(A) A polyol component selected from the group consisting of polyether polyol, polyether ester polyol, polyester polyol and polyurethane polyol, (B) a polyisocyanate compound having an isocyanate group at the terminal, and (C) 2- A solventless adhesive composition containing butyl-2-ethyl-1,3-propanediol and / or polyethylene glycol having a number average molecular weight of 100 to 3000.
[Selection figure] None

Description

  The present invention relates to a solventless adhesive composition and a laminate using the same, and more particularly, to a solventless adhesive composition useful as a packaging material for foods, medical products, cosmetics, and the like, and the use thereof. Relates to the laminated body.

  The pasting of various plastic films and the pasting of a plastic film with a metal vapor-deposited film or a metal foil have been conventionally performed by a dry laminating method using a hydroxyl group / isocyanate solvent adhesive. However, since the dry laminate method uses an adhesive containing an organic solvent, it has many problems such as environmental pollution due to exhaust, danger of fire explosion, sanitary obstruction of work environment.

  In recent years, the demand for removing organic solvents from adhesives has become stronger due to the demands for improving the working environment, strengthening the Fire Service Act, and regulating the release of VOC (volatile organic compounds) into the atmosphere. It is actively done. For example, JP-A-8-60131 discloses a solventless laminate adhesive composition comprising an organic polymer polyol and an organic polyisocyanate compound. Japanese Patent Application Laid-Open No. 2003-96428 discloses a solventless laminate adhesive composition in which the ratio of the hydroxyl group of the polyol component to the isocyanate group of the polyisocyanate component is hydroxyl group: isocyanate group = 1: 1 to 1: 3. Has been. These adhesive compositions have no problem when the films are bonded together, but when bonding metal-deposited films that require higher barrier performance in food packaging, etc. There existed a problem that a pattern generate | occur | produced and the external appearance defect will arise.

As a method for improving the appearance defect, a method for reducing the viscosity of the adhesive has been proposed (Japanese Patent Laid-Open Nos. 8-283691 and 2002-249745). However, a satisfactory paint appearance is still not obtained. Not in. Furthermore, if the viscosity of the adhesive is lowered, the adhesive performance is inferior, so it can be applied to the adhesion between films such as stretched polypropylene film and unstretched polypropylene film, but it has good adhesion to metal vapor deposited films and metal foils. There was a problem that it could not be obtained.
In addition, mixing of powder as another method for improving the appearance has been proposed (Japanese Patent Laid-Open No. 2011-162579). When the adhesive described in the above publication is used, the adhesive layer after bonding is transparent and the adhesive performance is good, but the appearance of the solventless adhesive before bonding is not good There was a problem above.

JP-A-8-60131 JP 2003-96428 A JP-A-8-283691 JP 2002-249745 A JP 2011-162579 A

  The object of the present invention is to solve the above-mentioned problems of the prior art, and even when various plastic films and metal-deposited films or metal foils are bonded to each other, a good paint appearance is produced without causing a “Yuzu skin” -like appearance defect. Thus, the present invention provides a solventless adhesive composition that is satisfactory in adhesive performance and that is transparent even before bonding.

The present invention comprises (A) a polyether polyol (excluding polyethylene glycol in (C) below), a polyether ester polyol, a polyester polyol, a polyol component selected from the group consisting of a polyurethane polyol, and (B) the terminal. A solvent-free adhesive comprising a polyisocyanate compound having an isocyanate group and (C) 2-butyl-2-ethyl-1,3-propanediol or / and polyethylene glycol having a number average molecular weight of 100 to 3000 Agent composition,
It is preferable to contain 0.5 to 30 parts by weight of the component (C) with respect to 100 parts by weight of the polyol component (A).
It is preferable that the melt viscosity at 70 ° C. immediately after mixing the component (A), the component (B) and the component (C) is 50 to 5000 mPa · s.

  Moreover, this invention relates to the laminated body formed by laminating | stacking a sheet-like base material using the said solventless type adhesive composition.

  The solventless adhesive composition of the present invention is excellent in transparency, and even when various plastic films and a metal vapor-deposited film or a metal foil are bonded together, good adhesion performance can be obtained without causing appearance defects. it can.

  The solvent-free adhesive composition of the present invention is a polyol selected from the group consisting of (A) polyether polyol (excluding polyethylene glycol in (C) below), polyether ester polyol, polyester polyol, and polyurethane polyol. The component, (B) a polyisocyanate compound having an isocyanate group at the terminal, and (C) 2-butyl-2-ethyl-1,3-propanediol or / and a polyethylene glycol having a number average molecular weight of 100 to 3000 are contained.

  In the present invention, as the polyol component (A), one or more polyols selected from the group consisting of polyether polyols, polyether ester polyols, polyester polyols, and polyurethane polyols are used.

  As the polyether polyol, for example, an oxirane compound such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran is polymerized using, for example, water, ethylene glycol, propylene glycol, trimethylolpropane, and glycerin as a low molecular weight polyol as an initiator. Examples include polyether polyols obtained.

  The polyether ester polyol can be obtained, for example, by reacting the above-mentioned polyether polyol with a polycarboxylic acid such as terephthalic acid, isophthalic acid, adipic acid, azelaic acid, sebacic acid or the like or a mixture thereof. Examples include polyether ester polyols.

  Examples of the polyester polyol include polyvalent carboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, azelaic acid, and sebacic acid, or dialkyl esters thereof or mixtures thereof, and, for example, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol. , Neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3′-dimethylol heptane, polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, and other glycols Lactones such as polyester polyols or polycaprolactones, polyvalerolactones, poly (β-methyl-γ-valerolactones) obtained by reacting them with a mixture thereof And polyester polyols obtained by ring-opening polymerization.

  The polyurethane polyol is a polyol having a urethane bond in one molecule. For example, a polyester polyol, polyether polyol, polyether ester polyol or the like having a number average molecular weight of 200 to 20,000 and an organic polyisocyanate are combined with an isocyanate group / It is obtained by reacting with a hydroxyl group (equivalent ratio) of less than 1, preferably 0.9 or less. Examples of the organic polyisocyanate used include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2, Aliphatic diisocyanates such as 1,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methylcaproate; 1,4-cyclohexane diisocyanate, 3-isocyanate methyl-3,5,5- Trimethylcyclohexyl isocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), methyl-2,4-cyclohexanediisocyanate, methyl-2,6-cyclohexane Cycloaliphatic diisocyanates such as sun diisocyanate, 1,4-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane; m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1 , 5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate or mixtures thereof, 4,4'-toluidine diisocyanate, dianidine diisocyanate, 4,4'-diphenyl ether diisocyanate, etc. 1,3- or 1,4-xylylene diisocyanate or mixtures thereof, ω, ω′-diisocyanate-1,4-diethylbenzene, 1,3 Or an araliphatic diisocyanate such as 1,4-bis (1-isocyanate-1-methylethyl) benzene or a mixture thereof; triphenylmethane-4,4 ′, 4 ″ -triisocyanate, 1,3,5-triisocyanate Benzene, organic triisocyanate such as 2,4,6-triisocyanate toluene, polyisocyanate monomer of organic tetraisocyanate such as 4,4′-diphenyldimethane-2,2′-5,5′-tetraisocyanate, Examples thereof include adducts, isocyanurates and burettes derived from the above polyisocyanate monomers.

In the present invention, a polyisocyanate compound having an isocyanate group at the terminal is used as the component (B). Examples of the polyisocyanate compound include polyisocyanate monomers exemplified as the organic polyisocyanate, dimers, trimers, burettes, allophanates, and adducts of the polyisocyanate monomers. Such polyisocyanate compounds may be used alone or in combination of two or more.
The adduct body can be produced by reacting a polyisocyanate monomer with a trihydric or higher alcohol. Examples of trihydric or higher alcohols include glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexatriol, 1,2,4-butanetriol, sorbitol, pentaerythritol and the like.

The trimer is a trimer of a polyisocyanate monomer and is represented by the following general formula (1).
In the formula (1), R is a residue excluding one NCO of the polyisocyanate monomer.

  The burette body is represented by the formula R—NH—CO—NR′—CO—NH—R, wherein R is a residue other than one NCO of the polyisocyanate monomer, and R ′ is H or monovalent substitution. It is a group. In the burette body, after reacting two molecules of polyisocyanate monomer and one molecule of water, one more molecule of polyisocyanate monomer is reacted, or two molecules of polyisocyanate monomer and one molecule of first molecule are reacted. It can be obtained by reacting a primary amine compound.

  In order to obtain a polyisocyanate compound having an isocyanate group which is the component (B) in the solventless adhesive composition of the present invention, the equivalent ratio of isocyanate group / hydroxyl group is appropriately selected, but preferably 1 to 6 More preferably, it is 1.5-4. When the said equivalent ratio is less than 1, it becomes a terminal hydroxyl group and the compound of terminal isocyanate may not be obtained. On the other hand, when the equivalent ratio exceeds 6, the molecular weight does not increase, and at the same time, since there are many isocyanate groups, the coating film becomes hard when mixed with the component (A) and used as an adhesive, resulting in high adhesive strength. It may not be obtained.

In the present invention, the component (C) contains 2-butyl-2-ethyl-1,3-propanediol or / and polyethylene glycol having a number average molecular weight of 100 to 3000. The content of component (C) is preferably 0.5 to 30 parts by weight and more preferably 5 to 30 parts by weight with respect to 100 parts by weight of (A) polyol component. If the amount is less than 0.5 part by weight, the yarn drawing phenomenon cannot be sufficiently reduced, and the coating film may be non-uniform. On the other hand, if it exceeds 30 parts by weight, the physical properties may be deteriorated.
The number average molecular weight of polyethylene glycol is preferably 100 to 1000. If the molecular weight is larger than 3000, the viscosity of the adhesive is improved, and the film may be roughened during coating. On the other hand, if the molecular weight is 100 or less, the stringing phenomenon cannot be sufficiently reduced, and the coating film may become non-uniform.

  By containing the component (C), the solventless adhesive composition of the present invention improves transparency as an adhesive, and an excellent coating appearance and good adhesion performance can be obtained. The reason why the transparency as an adhesive is improved is that the component (C) exhibits good compatibility with the component (A) and / or the component (B). The solvent-free adhesive composition containing the component (C) exhibits flow characteristics that are easy to relieve stress, and can reduce the stringing phenomenon between coating rolls during coating. As a result, it is possible to suppress the entrainment of bubbles at the time of nip, which is caused by the rough surface of the coating, and a good appearance can be obtained.

In the adhesive of the present invention, it is preferable to blend the component (C) with the polyol component (A) and then blend the component (B). It is preferable to mix | blend each component as low as possible in the range which can ensure fluidity | liquidity, specifically, it is preferable to mix | blend at 25-80 degreeC.
The melt viscosity at 70 ° C. immediately after mixing the component (A), the component (B) and the component (C) is preferably 50 to 5000 mPa · s, more preferably 100 to 3000 mPa · s.
In the present invention, “immediately after mixing” means within 1 minute after uniform mixing, and the melt viscosity is a value determined by a B-type viscometer. When the melt viscosity at 70 ° C. exceeds 5,000 mPa · s, coating becomes difficult and it is difficult to ensure good workability, and even when the coating temperature is raised to 100 ° C., a good coating appearance tends not to be obtained. It is in. When the coating is performed at 100 ° C. or higher, the film is stretched and the pitch of the printed pattern is shifted, so that the lamination cannot be performed. On the other hand, if the melt viscosity at 70 ° C. is less than 50 mPa · s, the initial cohesive force is weak, so that sufficient adhesion performance cannot be obtained, or the thickness of the coating film becomes uniform when the adhesive is applied to the substrate. It tends to cause poor appearance or warp.
The solventless adhesive composition of the present invention further includes, for example, antioxidants, ultraviolet absorbers, hydrolysis inhibitors, antifungal agents, thickeners, plasticizers, antifoaming agents, pigments, fillers and the like. Additives can be used as needed. Moreover, in order to further improve the adhesive performance, an adhesion aid such as a silane coupling agent, phosphoric acid, phosphoric acid derivative, acid anhydride, or adhesive resin can be used. In addition, known catalysts, additives and the like can be used to control the curing reaction.

The method of using the solventless adhesive composition of the present invention includes (A) a polyol component, (B) a polyisocyanate compound and (C) 2-butyl-2-ethyl-1,3-propanediol or / and a number average. Polyethylene glycol having a molecular weight of 100 to 3000 is mixed, and the adhesive composition is applied to the surface of the sheet-like substrate by a solventless laminator. Thereafter, the adhesive surface of the sheet-like substrate and another sheet-like substrate are bonded together, and cured by curing at room temperature or under heating. The coating amount of the adhesive composition is appropriately selected according to the type of substrate, coating conditions, etc., but is usually 1.0 to 5.0 g / m ² , preferably 1.5 to 4. 5 g / m ² .

A laminate can be obtained by laminating a sheet-like substrate using the solventless adhesive composition of the present invention.
As the sheet-like substrate, a plastic film such as polyester, polyamide, polyethylene, or polypropylene, a metal vapor deposition film obtained by vapor deposition of aluminum, silicon oxide, aluminum oxide, or the like, or a metal foil such as stainless steel, iron, copper, or lead is used. Such a combination of substrates may be a plastic film or a plastic film and a metal vapor deposition film or a metal foil.

  Hereinafter, the present invention will be described more specifically with reference to examples. Unless otherwise indicated,% and part in Examples and Comparative Examples are based on mass.

The number average molecular weights of polyurethane polyol, polyether ester polyol, and polyethylene glycol were obtained from gel permeation chromatography (GPC) and calculated as standard polystyrene equivalent values. The melt viscosity at 70 ° C. was determined with a B-type viscometer.
(Synthesis Example A-1)
Reaction of 30 parts of polypropylene glycol having a number average molecular weight of about 400, 40 parts of polypropylene glycol having a number average molecular weight of about 2000, 20 parts of triol having a number average molecular weight of about 3000 obtained by adding polypropylene glycol to glycerin, and 10 parts of 4,4′-diphenylmethane diisocyanate The urethanization reaction was performed by charging in a container and heating at 70 ° C. to 80 ° C. for 3 hours while stirring under a nitrogen gas stream. A polyether polyurethane polyol resin having hydroxyl groups at both ends having a number average molecular weight of 2000 was obtained. Hereinafter, this resin is referred to as polyol A- (1).

(Synthesis Example A-2)
While stirring 100 parts of polyol A- (1) obtained in Synthesis Example A-1 under a nitrogen gas stream at 70 ° C., 5 parts of 2-butyl-2-ethyl-1,3-propanediol and a number average molecular weight After adding 5 parts of 2000 polyethylene glycol, the mixture was stirred for 1 hour to obtain a polyol. Hereinafter, this polyol is referred to as polyol A- (2).

(Synthesis Example A-3)
70 parts of polypropylene glycol having a number average molecular weight of about 1000, 20 parts of polypropylene glycol having a number average molecular weight of about 400, 10 parts of 4,4′-diphenylmethane diisocyanate, and 20 parts of a burette of hexamethylene diisocyanate are stirred under a nitrogen gas stream. The urethanization reaction was carried out by heating at -80 ° C for 3 hours. A polyether polyurethane polyol resin having hydroxyl groups at both ends having a number average molecular weight of 2000 was obtained. Hereinafter, this resin is referred to as polyol A- (3).

(Synthesis Example A-4)
While stirring 100 parts of polyol A- (3) obtained in Synthesis Example A-3 under a nitrogen gas stream at 70 ° C., 10 parts of 2-butyl-2-ethyl-1,3-propanediol and a number average molecular weight After adding 10 parts of 2000 polyethylene glycol, the mixture was stirred for 1 hour to obtain a polyol.
Hereinafter, this polyol is described as polyol A- (4).

(Synthesis Example A-5)
A reaction vessel containing 95 parts of a polyether polyester polyether (trade name: Adeka New Ace F7-67, manufactured by Asahi Denka Kogyo Co., Ltd.) having a number-average molecular weight of about 2000 mainly composed of adipic acid and propylene glycol, and 5 parts trimethylolpropane The mixture was heated at 150 to 180 ° C. for 2 hours with stirring under a nitrogen gas stream to conduct a transesterification reaction. A polyether polyester polyol resin having hydroxyl groups at both ends having a number average molecular weight of about 1800 was obtained. Hereinafter, this resin is described as polyol A- (5).

(Synthesis Example A-6)
While stirring 100 parts of polyol A- (5) obtained in Synthesis Example A-5 under a nitrogen gas stream at 70 ° C., 30 parts of 2-butyl-2-ethyl-1,3-propanediol was stirred for 1 hour. Thus, a polyol was obtained. Hereinafter, this polyol is referred to as polyol A- (6).

(Synthesis Example A-7)
While stirring 100 parts of Polyol A- (5) obtained in Synthesis Example A-5 under a nitrogen gas stream at 70 ° C., 30 parts of polyethylene glycol having a number average molecular weight of 1000 was added, followed by stirring for 1 hour to obtain a polyol. It was. Hereinafter, this polyol is referred to as polyol A- (7).

(Synthesis Example A-8)
While stirring 100 parts of polyol A- (1) obtained in Synthesis Example A-1 under a nitrogen gas stream at 70 ° C., silica powder having an average particle size of 2.5 × 10 −3 mm (Fuji Silysia Chemical Ltd. (Product name: Silicia 430) 0.5 part was added and stirred for 1 hour to obtain a polyol containing silica powder. Hereinafter, this polyol is referred to as polyol A- (8).

(Synthesis Example A-9)
While stirring 100 parts of polyol A- (1) obtained in Synthesis Example A-1 under a nitrogen gas stream at 70 ° C., zeolite powder having an average particle size of 1.5 × 10 −3 mm (manufactured by Mizusawa Chemical Co., Ltd.) Then, 1 part of a trade name: Shilton JC-20) was added and stirred for 1 hour to obtain a polyol containing silica powder. Hereinafter, this polyol is referred to as polyol A- (9).

(Synthesis Example B-1)
Charge 50 parts of adduct body of trimethylolpropane, 2,4- and 2,6-tolylene diisocyanate, and 50 parts of isophorone diisocyanate to a reaction vessel and heat at 100 ° C. to 120 ° C. for 50 minutes with stirring under a nitrogen gas stream. A polyisocyanate mixture was obtained. Hereinafter, this polyisocyanate mixture is referred to as polyisocyanate B- (1).

Example 1
100 parts of polyol A- (1) obtained in Synthesis Example A-1 was charged in a container and dissolved by heating at 50 ° C. to 70 ° C. for 50 minutes while stirring under a nitrogen gas stream. Subsequently, 50 parts of polyisocyanate B- (1) obtained in Synthesis Example B-1 was mixed at 80 ° C. to obtain a solventless adhesive composition.
It was 600 mPa * s when the melt viscosity at 70 degreeC of this composition was measured when 1 minute passed after uniform mixing.
Further, according to the following methods, the appearance, coating appearance, and adhesive strength of the adhesive coating liquid were evaluated. The results are shown in Table 1.

(Examples 2-4, Comparative Examples 1-5)
A solventless adhesive composition was obtained in the same manner as in Example 1 except that the polyol and polyisocyanate shown in Table 1 were used at a predetermined ratio, and the melt viscosity at 70 ° C. was measured.
Moreover, it carried out similarly to Example 1, and evaluated the external appearance, coating external appearance, and adhesive force of the adhesive coating liquid. The results are shown in Table 1.

<Evaluation of solventless adhesive composition>
[Appearance of adhesive coating solution]
In parallel with the melt viscosity measurement, an adhesive coating liquid at 70 ° C. that had passed for 1 minute after uniform mixing was placed in a 140 ml glass container, and the appearance (transparency) of the coating liquid was visually observed.

[Production of laminate]
The surface of a PET (polyethylene terephthalate) film (thickness: 12 μm) was coated with the solventless adhesive composition obtained in each of the above Examples or Comparative Examples adjusted to 70 ° C. using a solventless test coater (coating) (Amount: 2.0 g / m 2), an aluminum-deposited unstretched polypropylene film (VMPP, thickness: 25 μm) was laminated on the coated surface. These laminates were placed in a constant temperature bath at 40 ° C. and left for 2 days to prepare a laminate film. About each obtained laminated film, the coating external appearance and adhesive force were observed and measured in the following way, and those results were shown in Table 1.

(Paint appearance)
The appearance of the laminate film applied was visually observed. When the laminated film was observed from the side of the PET film, the coating film had a uniform coating surface, with the surface of the underlying vapor-deposited film without any skin-like pattern or small speckled pattern. Table 1 shows a case where “good” was observed, and a case where many yuzu skin-like patterns and small spots were observed as “bad”.

(Adhesive strength)
The laminate film was cut into a length of 300 mm and a width of 15 mm to obtain a test piece. Using an Instron type tensile tester, the sample was pulled at a peel rate of 300 mm / min, and the T-type peel strength (N / 15 mm) between PET / VMCP was measured. This test was performed 5 times, and the average value was obtained.

  From Table 1, it can be seen that Examples 1 to 4 have good adhesive coating liquid appearance, coating appearance and excellent adhesive strength. On the other hand, in Comparative Examples 1 to 5, it can be seen that the adhesive coating liquid is opaque, the coating appearance is poor, or the adhesive strength is poor.

Claims (4)

(A) Polyether component selected from the group consisting of polyether polyol (excluding polyethylene glycol in (C) below), polyether ester polyol, polyester polyol, polyurethane polyol;
(B) a polyisocyanate compound having an isocyanate group at the terminal;
(C) A solventless adhesive composition comprising 2-butyl-2-ethyl-1,3-propanediol or / and polyethylene glycol having a number average molecular weight of 100 to 3000.   0.5 to 30 parts by weight of 2-butyl-2-ethyl-1,3-propanediol or / and polyethylene glycol (C) having a number average molecular weight of 100 to 3000 with respect to 100 parts by weight of the polyol component (A), The solventless adhesive composition according to claim 1, which is contained.   The solvent-free adhesive according to claim 1 or 2, wherein the melt viscosity at 70 ° C immediately after mixing the component (A), the component (B) and the component (C) is 50 to 5000 mPa · s. Agent composition.   The laminated body formed by laminating | stacking a sheet-like base material using the solventless adhesive composition of any one of Claims 1-3.