JPH11348136A - Method for producing multilayer resin stretched film - Google Patents

Abstract

(57) [Problem] To provide a method for producing a multilayer resin stretched film which has excellent suitability for printing, embossing, and backing, and has high surface strength. The surface of a base layer (A) containing 40 to 85% by weight of a thermoplastic resin and 60 to 15% by weight of an inorganic or organic fine powder has a melting point higher than that of the thermoplastic resin of the base layer (A). 30 to 90% by weight of a thermoplastic resin having an average particle diameter smaller than that of the inorganic or organic fine particles of the base material layer (A) by 70 to 90% by weight or lower.
A method for producing a multilayer resin stretched film, comprising: forming a surface layer (B) containing 10% by weight, and stretching the film at a temperature lower than the melting point of the thermoplastic resin of the surface layer (B) by 5 ° C. or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a stretched multilayer resin film which has excellent suitability for printing, embossing and backing and has high surface strength. The multilayer resin stretched film produced by the production method of the present invention can be used for various applications including architectural decorative materials having fine pores.

[0002]

2. Description of the Related Art Vinyl chloride resins such as vinyl chloride resins and vinyl chloride / vinyl acetate copolymer resins are known as thermoplastic resins having excellent printability and embossability. Vinyl chloride-based resins are widely used in industry because their hardness can be easily adjusted by a plasticizer and they are inexpensive. For this reason, many films mainly composed of a vinyl chloride resin are also used as resin films used for architectural decoration materials. However, the vinyl chloride-based resin has a problem that harmful gases such as chlorine gas and hydrogen chloride gas are generated at the time of waste treatment or fire, which causes deterioration of the incinerator and environmental pollution. There is also a problem that the interior of the room is contaminated by bleeding of the plasticizer, and the use thereof tends to be regulated worldwide.

In order to solve these problems, materials using polyolefin resins instead of vinyl chloride resins have been actively developed in recent years. However, a material using a polyolefin resin has a disadvantage that it has crystallinity. Further, in the case of a stretched film, there is also a problem that embossing is worse than that of a vinyl chloride film due to the orientation of molecules by stretching. Also,
When printing a pattern by gravure printing, silk screen printing, offset rotary printing, aqueous flexographic printing, or the like, it has been pointed out that the ink has poor adhesion, and that multicolor printing causes a shift in the pattern.

[0004] In order to improve the ink adhesion, an anchor treatment or the like is generally performed on the film surface, but this is not practical because the production cost is increased. Further, for example, in the case of performing multicolor printing using a polyolefin-based unstretched film, since the tensile strength in the printing direction is low, the printing must be performed with a low film tension, which causes the film to meander. In order to prevent such meandering, when the tension of the film is increased, the film is easily stretched to cause a dimensional change. Therefore, when printing the first color and the second and subsequent colors, the pattern is shifted and high-definition printing cannot be performed. There is also a disadvantage.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve these problems of the prior art. That is, an object of the present invention is to provide a method for producing a multilayer resin stretched film having high surface strength, excellent embossability, and good ink adhesion. Another object of the present invention is to provide a method for producing an inexpensive multilayer resin stretched film which is excellent in backing workability and can be effectively used as a building decoration material or the like. Further, the present invention has an object to solve the problem of providing a method for producing a stretched multilayer resin film which does not cause environmental pollution and does not deteriorate the incinerator during waste treatment.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, by controlling the melting point and the stretching temperature of the thermoplastic resin used for the multilayer resin stretched film, the present invention has been developed. The present inventors have found that a multilayer resin stretched film having excellent properties meeting the purpose of the present invention can be manufactured, and the present invention has been completed.

That is, the present invention relates to
On the surface of the base layer (A) containing 5% by weight and 60 to 15% by weight of an inorganic or organic fine powder, the base layer (A)
30 to 90% by weight of a thermoplastic resin having a melting point lower than that of the thermoplastic resin by 10 ° C. or more, and 70 to 10% by weight of an inorganic or organic fine powder having an average particle diameter smaller than that of the inorganic or organic fine particles of the base layer (A). % Of the surface layer (B) containing the thermoplastic resin of the surface layer (B).
An object of the present invention is to provide a method for producing a multilayer resin stretched film including a step of stretching at a temperature lower than or equal to ° C.

[0008] In a preferred embodiment of the present invention, the thermoplastic resin 30 to 30 is coated on the back surface of the base material layer (A) before stretching.
A step of forming a back layer (C) containing 70% by weight and 70 to 30% by weight of inorganic fine powder is further performed. Also,
After stretching, the surface layer (B) may be embossed. The stretching is desirably uniaxial stretching, and is preferably performed under the condition that the porosity of the multilayer resin stretched film calculated by the formula (1) is in the range of 5 to 60%.

[0009]

(Equation 2) ρ0: True density of stretched multilayer resin film ρ1: Density of stretched multilayer resin film

The average particle diameter of the inorganic or organic fine powder of the base layer (A) is in the range of 0.6 to 3 μm, and the average particle diameter of the inorganic or organic fine powder of the surface layer (B) is 0.1 to 2 μm.
The average particle diameter of the inorganic or organic fine powder of the back surface layer (C) can be preferably set in the range of 0.6 to 3 μm. Further, it is preferable to use an inorganic fine powder whose surface is subjected to a hydrophilic treatment for the back surface layer (C). As the thermoplastic resin of the base layer (A), the surface layer (B) and the back layer (C), a polyolefin resin, an olefin thermoplastic elastomer, or a mixture of a polyolefin resin and an olefin thermoplastic elastomer is used. be able to. A mixture of a polyolefin resin and an olefin thermoplastic elastomer is a polyolefin resin 1
It is preferable that the olefinic thermoplastic elastomer be contained in an amount of 5 to 100 parts by weight with respect to 00 parts by weight.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. The method for producing a stretched multilayer resin film of the present invention includes at least a step of forming a surface layer (B) on the surface of a base material layer (A) and a step of stretching the formed laminate.

[0012]Laminate forming process  In a preferred embodiment of the present invention, the base material layer is provided before the stretching step.
A back surface layer (C) is formed on the back surface of (A). Back layer (C)
Is formed before forming the surface layer (B) on the base material layer (A).
May or may not be. In some cases,
A surface layer (B) and a back layer (C) on both sides of the layer (A) at the same time
It may be formed. Base material layer formed by the production method of the present invention
(A), the surface layer (B) and the back layer (C)
Contains thermoplastic resin and inorganic or organic fine powder
You.

The type of the thermoplastic resin used for the base layer (A), front layer (B) and back layer (C) is not particularly limited. For example, polyolefin resin; polyamide resin such as nylon-6, nylon-6,6, nylon-6, T; heat of polyethylene terephthalate or a copolymer thereof, polybutylene terephthalate or a copolymer thereof, or aliphatic polyester. Plastic polyester-based resin; polycarbonate, atactic polystyrene, syndiotactic polystyrene and the like can be used.

Among them, it is preferable to use a non-polar polyolefin resin. Examples of the polyolefin resin include ethylene, propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, and 4-methyl-1.
-Carbon number 2 such as pentene and 3-methyl-1-pentene;
And a copolymer of 2 to 5 kinds of these α-olefins. The copolymer may be a random copolymer or a block copolymer.
Specifically, the density is 0.89 to 0.97 g / cm ³ , and the melt flow rate (190 ° C., 2.16 kg load) is 1 to
Branched polyethylene, linear polyethylene at 10 g / 10 min; propylene homopolymer having a melt flow rate (230 ° C., 2.16 kg load) of 0.2 to 8 g / 10 min;
Propylene / ethylene copolymer, propylene / 1-butene copolymer, propylene / ethylene / 1-butene copolymer, propylene / 4-methyl-1-pentene copolymer,
Propylene / 3-methyl-1-pentene copolymer, poly (1-butene), poly (4-methyl-1-pentene),
A propylene / ethylene / 3-methyl-1-pentene copolymer is exemplified. Among them, propylene homopolymer, propylene / ethylene random copolymer, and high-density polyethylene are preferable because they are inexpensive and have good moldability.

For the base material layer (A), the surface layer (B) and the back surface layer (C), a thermoplastic elastomer can be particularly selected and used as the thermoplastic resin. As used herein, the term “thermoplastic elastomer” includes both a rubber component having elasticity in a molecule (soft segment) and a molecular constraint component (hard segment) for preventing plastic deformation. While the hard segment acts as the point of flow of the flowable rubber and exhibits rubber-like properties, the hard segment is melted by heating to exhibit flow characteristics as a thermoplastic resin. In the present specification, other thermoplastic resins are referred to as “thermoplastic non-elastomers”.

A large number of thermoplastic elastomers having different types, molecular weights, arrangements, and the like of soft segments and hard segments are known. For example, examples of the styrene-based thermoplastic elastomer include Tuftec (trade name) manufactured by Asahi Kasei Kogyo Co., Ltd. and Lavalon (trade name) manufactured by Mitsubishi Chemical Corporation. Examples of the olefin-based thermoplastic elastomer include Mirastomer (trade name) manufactured by Mitsui Petrochemical Industries, Ltd. and Thermolan (trade name) manufactured by Mitsubishi Chemical Corporation.
As polyester-based thermoplastic elastomer, Toray
Hytrel (trade name) manufactured by DuPont, Toyobo
There is Pelprene (trade name). In addition, polyurethane thermoplastic elastomers and the like are known.

For the base material layer (A), the surface layer (B) and the back surface layer (C), one of the above-mentioned thermoplastic resins may be selected and used alone. At least one species may be selected and used in combination. When two or more kinds are used in combination, it is preferable to use a mixture of a thermoplastic non-elastomer and a thermoplastic elastomer. The mixing ratio is preferably 5 to 100 parts by weight of the thermoplastic elastomer per 100 parts by weight of the thermoplastic non-elastomer. Particularly, the blending amount of the thermoplastic elastomer is 5 to 50 parts by weight in the base layer (A) and 20 to 100 parts by weight in the surface layer (B).
In terms of parts by weight, the amount of pores in the base material layer (A) is
It is preferable because the content can be increased to improve embossability, printability, and surface strength of the surface layer (B).

The same thermoplastic resin or different thermoplastic resins may be used for the base layer (A), the surface layer (B) and the back layer (C). The thermoplastic resin can be appropriately selected according to the properties required for each layer. In order to use it as an architectural decoration material or the like, the surface layer (B) is often subjected to various types of printing, and then to a processing such as embossing. For this reason,
The surface layer (B) is required to have high-definition printability by various printing methods and ink adhesion strength capable of preventing ink dropout during embossing. In order to sufficiently meet these requirements, the surface layer (B) has a melting point 10 times higher than that of the base material layer (A).
Use a thermoplastic resin that is lower than ℃. The melting point of the thermoplastic resin used for the back layer (C) is not particularly limited, and may be the same as the melting point of the thermoplastic resin of the base layer (A) or the surface layer (B). May be different from the melting point of.

The kind of the organic or inorganic fine powder used for the base material layer (A), the surface layer (B) and the back layer (C) is not particularly limited. Examples of the inorganic fine powder include heavy calcium carbonate, light calcium carbonate, clay, talc, titanium oxide, barium sulfate, zinc oxide, magnesium oxide, diatomaceous earth, and silicon oxide. Of these, heavy calcium carbonate, clay, and diatomaceous earth are preferred because they are inexpensive and have good porosity during stretching.

Examples of the organic fine powder include polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, polyethylene naphthalate, polystyrene, melamine resin, polyethylene sulphite, polyimide, polyethyl ether ketone, polyphenylene sulphite and the like. Among them, it is preferable to use incompatible fine powder having a melting point higher than that of the thermoplastic resin to be used from the viewpoint of pore formation.

For the base material layer (A), the surface layer (B) and the back surface layer (C), one of the above fine powders may be selected and used alone, or two of them may be used alone. The above may be selected and used in combination. When two or more kinds are used in combination, an organic fine powder and an inorganic fine powder may be mixed and used. Further, the same fine powder or different fine powders may be used for the base material layer (A), the surface layer (B) and the back layer (C). However, as the fine powder of the base material layer (B), a fine powder having an average particle diameter smaller than that of the fine powder of the surface layer (A) is selected. By adjusting the average particle diameter in this way, surface protrusions after stretching are reduced, and the surface smoothness and the like are improved, and as a result, printing with higher definition can be performed.

The preferable range of the average particle size of the fine powder used in the base material layer (A) is 0.6 to 3 μm. If the average particle diameter is 0.6 μm or more, more sufficient voids (voids) can be formed by stretching. If the average particle size is 3 μm or less, the pores can be controlled to an appropriate size, and the occurrence of wrinkles in the film can be more effectively prevented. The preferable range of the average particle diameter of the fine powder used for the surface layer (B) is 0.1 to 2 μm. By setting the average particle diameter within the above range, fine cracks can be formed on the surface to improve the adhesiveness of the ink, and white spots during printing can be more effectively prevented. Further, in the surface layer (B), the content of coarse particles having a particle diameter of 44 μm or more which causes surface projections of the multilayer resin stretched film is preferably set to 10 ppm or less.

The preferable range of the average particle size of the fine powder used for the back layer (C) is 0.6 to 3 μm for the same reason as that for the fine powder of the base material layer (A). However, it is preferable to use an inorganic fine powder whose surface has been subjected to a hydrophilic treatment for the back surface layer (C). The hydrophilization treatment can be performed by treating the inorganic compound with a water-soluble anionic or cationic or nonionic polymer surfactant having an average molecular weight of 1,000 to 150,000 when wet-milling. In addition, it can also be carried out by treating the inorganic compound with an anion, a cation or a non-ionic antistatic agent during wet pulverization. Both of these processes may be performed in two stages. Preferred examples of the hydrophilized inorganic fine powder include those described in JP-A-7-300568.

The above two-stage treatment is carried out by applying an average particle diameter of 0.6 to 3
The use of the hydrophilic fine inorganic powder applied to the fine inorganic powder of μm makes it possible to adjust the contact angle (water contact angle) of the back surface layer (C) to water within a preferable range. The preferred range of the water contact angle is 10 to 80 °, and the more preferred range is 20 to 80 °.
70 °. If the contact angle with water is less than 10 °, the penetration rate of water becomes too high, and when an aqueous paste is used, the paste component itself permeates too much inside. For this reason, the amount of glue to be applied increases and the production cost increases. On the other hand, if the contact angle exceeds 80 °, the permeation rate of water is low and the drying property of the paste is low, so that the productivity is reduced and the production cost is increased. Further, since the permeation of the adhesive component itself is small, the adhesiveness between the adhesive and the stretched multilayer resin film is also reduced. In addition, the water contact angle in this specification shows what was measured using the contact angle meter (Kyowa Interface Chemical Co., Ltd. make, model CA-D).

As described above, by using the inorganic fine powder subjected to the hydrophilic treatment for the back layer (C) and improving the wettability with water, the adsorbability of the aqueous adhesive or the like to the back layer (C) is improved. And drying properties are improved. Further, by using the inorganic fine powder treated with the antistatic agent, the back surface layer (C) can be provided with an antistatic property. Therefore, it is possible to obtain a stretched multilayer resin film which is free from charging trouble at the time of applying an adhesive or a pressure-sensitive adhesive such as a backing and has excellent drying properties and excellent adhesiveness.

In the production method of the present invention, each layer is formed by mixing the thermoplastic resin and the fine powder. In the base material layer (A), 40 to 85% by weight of a thermoplastic resin and 60 to 15% by weight of an inorganic or organic fine powder are blended. If the amount of the fine powder exceeds 60% by weight, it is difficult to form a multilayer resin stretched film having a uniform thickness, and if the amount is less than 15% by weight, the amount of pores formed by stretching is small, so that embossability is poor. turn into.

In the surface layer (B), a thermoplastic resin is used in an amount of 30 to
90% by weight, and 70 to 10% by weight of inorganic or organic fine powder. When the amount of the fine powder exceeds 70% by weight, it is difficult to uniformly stretch the film, and the surface film of the produced multilayer resin stretched film is liable to be cracked, which is not practical. If the amount of the fine powder is less than 10% by weight, ink adhesion will be poor. In the back surface layer (C), 30 to 70% by weight of a thermoplastic resin and 70 to 30% by weight of an inorganic or organic fine powder are blended. If the amount of the fine powder exceeds 70% by weight, it becomes difficult to form a multilayer resin stretched film having a uniform thickness. In particular, the inorganic fine powder subjected to the hydrophilization treatment is preferably used in an amount of 10% by weight or more for exhibiting hydrophilicity.

When the fine powder is mixed and kneaded in the thermoplastic resin, a dispersant, an antioxidant, a compatibilizer, a flame retardant, an ultraviolet stabilizer, a coloring pigment, and the like can be added as necessary. In particular, it is preferable that the base layer (A) and the surface layer (B) are colored to a desired color by using an inorganic or organic coloring pigment. When a stretched multilayer resin film is used as a durable material, it is preferable to add an antioxidant, an ultraviolet stabilizer, and the like. Furthermore, when an organic fine powder is used, the type and amount of the compatibilizer are important because they determine the particle form of the organic fine powder. Preferred examples of the compatibilizer include maleic acid-modified polypropylene (trade name: Umex, manufactured by Sanyo Chemical Industries, Ltd.). Further, the amount of the compatibilizer to be added is 10 g of the organic fine powder.
The amount is preferably 0.5 to 10 parts by weight with respect to 0 parts by weight.

A laminate is prepared using a blend containing a thermoplastic resin, fine powder and other additional components.
The thickness of each layer of the prepared laminate is as follows: surface layer (B) / base layer (A) / backside layer (C) = (1-3) / (8-4) / (1)
It is preferable to prepare so as to satisfy (3). By setting the thickness of each layer in this range, a multilayer resin stretched film having excellent surface strength, printability, embossability, and emboss return can be obtained. When the thickness configuration of the base material layer (A) is 4 or less, it is not preferable because embossing is deteriorated.

[0030]Stretching process  Low number of substrate layer (A), surface layer (B) and back layer (C)
The laminate comprising at least three layers is then subjected to a stretching step. 3 layers
According to the present invention, the three layers are separately formed.
Simple and inexpensive multilayer resin compared to the case where it is stretched into individual pieces and laminated
Stretched films can be produced. In addition, the present invention
According to the manufacturing method, the base layer (A) and the surface layer (B) are formed.
The control of the holes to be formed becomes easier. In particular, the base material layer (A)
Has more pores formed by stretching than the surface layer (B).
So that the base material layer (A) improves the embossing suitability
It is preferable to function effectively as a possible layer.

For stretching, various known methods can be used. The stretching temperature may be set to be equal to or higher than the glass transition temperature of the thermoplastic resin to be used in the case of the non-crystalline resin, or to be equal to or lower than the melting point of the crystal part in the case of the crystalline resin. it can. The stretching temperature is lower than the melting point of the thermoplastic resin of the surface layer (B) by 5 ° C. or more and 15 ° C. or lower than the melting point of the thermoplastic resin of the base layer (A). If the temperature is not set in this manner, the sheet sticks to the roll surface, especially when stretching between rolls is performed, and a sticking pattern appears on the multilayer resin stretched film surface.
Further, the number of cracks formed in the surface layer (B) is reduced, so that the ink adhesion is reduced.

Specific examples of the stretching method include inter-roll stretching using a peripheral speed difference between roll groups, and clip stretching using a tenter oven. Among them, uniaxial roll stretching is preferable because the stretching ratio can be arbitrarily adjusted and the size and number of pores formed can be controlled. In particular, by uniaxially stretching all the layers, holes and cracks are formed in the shape of a football, so that a larger number of fine holes can be formed than in biaxial stretching. In addition, since the resin is stretched and oriented in the flow direction of the film, it is possible to obtain a multilayer resin stretched film having higher tensile strength and less dimensional change due to tension during printing or processing than a non-stretched film.
Furthermore, since the orientation of the resin is less than in biaxial stretching,
A multilayer resin stretched film having good resistance to emboss return can be obtained.

The stretching ratio is not particularly limited, and is appropriately determined in consideration of the purpose of use of the stretched multilayer resin film and the properties of the thermoplastic resin used. For example, when a propylene homopolymer or a copolymer thereof is used as the thermoplastic resin, when the film is stretched in one direction, the ratio is about 1.2 to 12 times, preferably 2 to 7 times. Further, heat treatment at a high temperature is performed as necessary. The stretching speed is preferably from 20 to 350 m / min.

The produced multilayer resin stretched film has a porous structure having fine pores, and the above formula (1)
Is preferably in the range of 5 to 60%. If the porosity is less than 5%, embossing tends to be poor. On the other hand, if the porosity exceeds 60%, the material strength of the film is reduced, and the surface tends to be easily broken by cellophane tape or the like. Further, the porosity of each layer preferably satisfies the relationship of back layer (B) <base layer (A) <surface layer (C). While not being bound by any theory, by satisfying such porosity conditions, it becomes possible to absorb the thermal deformation of the resin portion that occurs during embossing, and to improve the embossability and return resistance. Is considered to be good. Also,
Since fine cracks are formed in the surface layer (B), printability is improved.

In formula (1), ρ0 represents the true density of the stretched multilayer resin film or each layer, and ρ1 represents the density of the stretched multilayer resin film or each layer. Unless the material before stretching contains a large amount of air, the true density is approximately equal to the density before stretching. The density of the multilayer resin stretched film is 0.60
It is preferably in the range of 〜1.20 g / cm ³ .

The stretched multilayer resin film produced by the production method of the present invention may be used as it is,
It may be used by being laminated on another thermoplastic film or the like. When further laminating, it can be laminated on a transparent or opaque film such as a polyester film, a polyamide film and a polyolefin film. The thickness of the multilayer resin stretched film is not particularly limited.
For example, 30 to 400 μm, preferably 60 to 200 μm
m. Further, by laminating the film with another film as described above, the overall thickness can be reduced to about 1 mm.

The produced multilayer resin stretched film can be used for various applications. For example, it is useful for wallpaper for architectural decoration, decorative paper for decorative plywood, flooring, interior materials for automobiles, tack labels that have been subjected to adhesive processing, and the like.

The surface layer (B) of the stretched multilayer resin film can be printed according to the purpose of use. The type and method of printing are not particularly limited. For example, printing can be performed using a known printing means such as gravure printing using an ink in which a pigment is dispersed in a known vehicle, aqueous flexo, silk screen, UV offset rotary printing, or the like. In addition, printing can be performed by metal deposition, gloss printing, mat printing, or the like. The pattern to be printed can be appropriately selected from natural patterns such as stones, wood, lattices, polka dots, and floral patterns, abstract patterns, characters, and the like.

The multilayer resin stretched film can be embossed. Embossing is generally performed after printing, but printing may be further performed after embossing. The embossing can be performed, for example, by using a known various press such as a lithographic press, a roll embossing machine, or an embossing machine to shape the concavo-convex shape of the embossing plate by heat or pressure. The roll embossing method is a method in which the concavo-convex shape of a cylindrical embossing plate is formed on a target material by hot pressing. The hot pressing is performed by heating the resin used for the surface layer (B) of the multilayer resin stretched film between the heat deformation temperature and the melting temperature, and pressing the embossing plate against the surface of the multilayer resin stretched film. After shaping, cooling is performed to fix the shape. As the heating method, for example, a method such as infrared irradiation, hot air blowing, conduction heat from a heating roller, dielectric heating, or the like is used. It should be noted that embossing can be performed simultaneously with film formation before or after stretching without using an embossing machine.

When the stretched multilayer resin film is used as a decorative plywood, the design can be improved by wiping after embossing and filling the recess with wiping ink. In particular, it is suitable for reproducing the appearance of the conduit portion of the grain.

It is desirable to form a surface protective layer made of a transparent resin layer on the outermost layer. The surface protective layer has a function of protecting the surface layer and imparting a three-dimensional effect to the design such as a pattern or emboss of the lower layer. Therefore, the surface protective layer is particularly useful when the multilayer resin stretched film is used as a decorative board or wallpaper. The surface protective layer can be formed by coating or bonding. In order to further improve the surface physical properties, it is preferable to use a colorless transparent or colored transparent resin having excellent surface physical properties such as weather resistance, abrasion resistance and stain resistance. Preferred as such a resin are, for example, various liquid acrylates, polyesters and other ionizing radiation-curable resins, two-component curable resins such as polyurethanes and unsaturated polyesters, fluororesins, polysiloxane resins and the like.
The surface protective layer may contain known antibacterial agents, antifungal agents, fragrances and the like.

Other materials can be attached to the back surface of the multilayer resin stretched film which has been subjected to various printing and embossing processes. For example, when used as wallpaper or flooring, backing paper or the like can be attached. The material used for the backing is not particularly limited, for example, thin paper, paper such as kraft paper, inorganic fiber such as glass fiber and carbon fiber, woven fabric, nonwoven fabric, resin film or sheet, metal foil, and simple substance such as woody material. Alternatively, a composite material obtained by laminating the above materials by a known means such as adhesion or heat fusion can be used.

Further, a laminated resin stretched film can be manufactured by laminating a multi-layer stretched resin film on a metal plate such as an iron plate or an aluminum plate by using an adhesive or heat fusion, for example, to produce a resin decorative plate lined with a plate-like material. Further, a resin decorative plywood can be manufactured by laminating a multilayer resin stretched film on various types of wood plywood with an adhesive. Furthermore, the pressure-sensitive adhesive layer on the backing, or the pressure-sensitive adhesive layer and a release sheet are laminated and formed,
Tack seal type wallpaper can also be manufactured.

[0044]

The present invention will be described more specifically with reference to the following Examples, Comparative Examples and Test Examples. The materials, usage amounts, ratios, operations, and the like shown below can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples. The materials used are summarized in the table below. In addition, MFR in a table | surface means a melt flow rate.

[0045]

[Table 1]

(Examples and Comparative Examples) According to the following procedures, a method for producing a multilayer resin stretched film of the present invention (Examples 1 to 5) and a comparative production method (Comparative Examples 1 to 3)
Was carried out, and wallpaper was produced using the films produced by these methods. Table 2 summarizes the types and amounts of materials used in the production of each film, the stretching conditions, and the states of the produced films. Formulations [A], [B] and [C] were prepared by mixing thermoplastic resin, elastomer and fine powder. These compounds were melt-kneaded with three extruders set at 250 ° C., respectively, and the compound [B] was laminated on the front side of the compound [A] and the compound [C] was laminated on the back side in a die. Then, the resultant was extruded and cooled to 70 ° C. by a cooling device to obtain a three-layer unstretched sheet. After heating this sheet to a predetermined temperature, it was stretched at a predetermined ratio between rolls in the longitudinal direction. Then, a discharge treatment machine (manufactured by Kasuga Electric Co., Ltd.) is provided on both sides of the obtained stretched film.
Was used to perform a corona treatment of 50 W / m ² · min to obtain a stretched multilayer resin film having a three-layer structure. The porosity of each layer of the obtained stretched multilayer resin film, the overall porosity, the thickness and the density were as shown in Table 2.

Next, gravure printing of a floral pattern (ink: manufactured by Toyo Ink Co., Ltd., trade name: “CCST”) was applied to the surface layer (B) of the stretched multilayer resin film, and then 100 ° C.
Was embossed with a heated embossing roll. Further, a UV curable resin (manufactured by Dainichi Seika) was applied on the surface so as to be 3 g / m ^2, and a high-pressure mercury lamp (8
(0 W, 10 m / min). Furthermore, 5 g of a water-soluble starch-based paste is applied to the back layer (C) of the multilayer resin stretched film.
/ M ² using a roll coater, and 8
After performing a drying treatment in a dryer set at 0 ° C., a release paper was backed to produce a wallpaper.

[0048]

[Table 2]

(Test Example) The following tests and evaluations were performed on the produced multilayer stretched resin film and wallpaper.

1) Embossability (hanging) The embossing formed on the surface of the wallpaper was visually observed and evaluated according to the following criteria. ：: Three-dimensional effect and sharpness △: Slightly lacking sharpness but three-dimensionality, no problem in practical use ×: Neither depth nor sharpness. Unavailable for practical use

2) Emboss return resistance The backing paper of the wallpaper was removed, and an appropriate amount of water was applied to the starch paste-coated surface with a brush, and the resultant was adhered to the surface of the plywood to prevent air from entering, thereby obtaining a wall plate. Immediately superimpose the two wall plates so that the surfaces on which the wallpapers are stuck are in contact with each other, and place them in a dryer at 60 ° C. for 30 minutes.
A pressurization of 0 kg / m ² was performed for 3 minutes. Thereafter, the wallboard was taken out, and the state change of the emboss was visually observed and evaluated according to the following criteria. ：: No change ：: The three-dimensional effect was slightly reduced, but there was no problem in practical use. Chipping, apparent embossing return, and practical problem x: Emboss is almost completely lost and cannot be used practically

3) Adhesiveness of ink on surface layer (B) Adhesive tape (trade name "Cellotape" manufactured by Nichiban Co., Ltd.) is applied to the surface of the gravure-printed wallpaper and pressed sufficiently. The film was peeled off at a constant speed in a direction at 90 degrees to the adhesive surface. The manner in which ink was removed from the wallpaper surface was visually observed and evaluated according to the following criteria. ：: The ink was not peeled at all. ○: The material portion of the film was destroyed, but there was no problem in practical use. ：: Tape There is resistance at the time of peeling, but most of the ink is peeled off, and there is a problem in practical use.
Unavailable for practical use

4) Surface Strength of Surface Layer (B) An adhesive tape (trade name “Cellotape” manufactured by Nichiban Co., Ltd.) was applied to the surface layer (B) of the multilayer resin stretched film, and pressed sufficiently with a finger. Use a tensile tester (manufactured by Shimadzu Corporation: trade name "Autograph") to apply 100
Peeling was performed at a speed of 0 mm / min. The state change of the surface layer (B) after peeling was observed with the naked eye and evaluated according to the following criteria. 変 化: No change ：: Very slight fluffing of the surface, but no problem in practical use △: Many fluffing of the surface There is a problem in practical use. ×: Peeling occurs from inside the film layer, and it cannot be used practically.

5) Water contact angle of back surface layer (C) The contact angle of the back surface layer (C) of the multilayer resin stretched film was measured using a contact angle meter (made by Kyowa Interface Chemical Co., Ltd .: Model CA- D).

6) Paste Drying Property of Back Layer (C) Starch paste (manufactured by Tokiwa Chemical Co.) is coated on the back layer (C) of the stretched multilayer resin film using a rod bar so that the solid content is 5 g / m ^2. Then, the time required for the coated starch paste to change its surface gloss was measured.

7) Adhesive Adhesion of Backside Layer (C) Adhesive tape (trade name “Cellotape” manufactured by Nichiban Co., Ltd.) is applied to the dried coated surface of the starch paste of 6), and after sufficiently pressing, the adhesive is applied. The tape was peeled off at a constant speed in a direction at 90 degrees to the adhesive surface. The manner in which the glue was removed was visually observed and evaluated according to the following criteria. ：: The adhesive is cohesively broken. ○: The material portion of the film is destroyed. ：: There is resistance when the tape is peeled off, but the glue is partially peeled off from the back layer (C), and there is a practical problem. X: Tape peeling Occasionally there is no resistance and the entire amount of glue peels off from the back layer (C), making it impractical

The results of the above tests are summarized in the following table. In the table, the difference between the melting point of the thermoplastic resin of the surface layer (B) and the stretching temperature (temperature difference X) and the melting point of the thermoplastic resin of the base layer (A) and the heat of the surface layer (B) are shown. The difference from the melting point of the plastic resin (temperature difference Y) is also described.

[Table 3]

As is clear from Table 3, the multilayer resin stretched film produced by the production method of the present invention has an embossing property, an emboss return resistance, an ink adhesion and a surface strength of the surface layer (B), and a back surface layer (C). ) Are good in water contact angle, glue drying property and glue adhesion (Examples 1 to 5)
5). On the other hand, when the stretching is performed at a temperature that does not satisfy the condition that the melting point of the thermoplastic resin of the surface layer (B) is 5 ° C. or more, or when the stretching is not performed,
The properties of the produced film are inferior and not practical.

[0059]

According to the method for producing a stretched multilayer resin film of the present invention, it is possible to provide a stretched multilayer resin film excellent in printing suitability, embossability, and backing suitability, and having high surface strength. . Therefore, according to the present invention, it is possible to effectively produce a multilayer resin stretched film that can be used for various uses including architectural decorative materials.

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[Procedure amendment]

[Submission date] July 6, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Method for producing a multilayer resin stretched film

[Claims]

(Equation 1) ρ0: True density of stretched multilayer resin film ρ1: Density of stretched multilayer resin film

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a stretched multilayer resin film which has excellent suitability for printing, embossing and backing and has high surface strength. The multilayer resin stretched film produced by the production method of the present invention can be used for various applications including architectural decorative materials having fine pores.

[0002]

2. Description of the Related Art Vinyl chloride resins such as vinyl chloride resins and vinyl chloride / vinyl acetate copolymer resins are known as thermoplastic resins having excellent printability and embossability. Vinyl chloride-based resins are widely used in industry because their hardness can be easily adjusted by a plasticizer and they are inexpensive. For this reason, many films mainly composed of a vinyl chloride resin are also used as resin films used for architectural decoration materials. However, the vinyl chloride-based resin has a problem that harmful gases such as chlorine gas and hydrogen chloride gas are generated at the time of waste treatment or fire, which causes deterioration of the incinerator and environmental pollution. There is also a problem that the interior of the room is contaminated by bleeding of the plasticizer, and the use thereof tends to be regulated worldwide.

In order to solve these problems, materials using polyolefin resins instead of vinyl chloride resins have been actively developed in recent years. However, a material using a polyolefin resin has a disadvantage that it has crystallinity. Further, in the case of a stretched film, there is also a problem that embossing is worse than that of a vinyl chloride film due to the orientation of molecules by stretching. Also,
When printing a pattern by gravure printing, silk screen printing, offset rotary printing, aqueous flexographic printing, or the like, it has been pointed out that the ink has poor adhesion, and that multicolor printing causes a shift in the pattern.

[0004] In order to improve the ink adhesion, an anchor treatment or the like is generally performed on the film surface, but this is not practical because the production cost is increased. Further, for example, in the case of performing multicolor printing using a polyolefin-based unstretched film, since the tensile strength in the printing direction is low, the printing must be performed with a low film tension, which causes the film to meander. In order to prevent such meandering, when the tension of the film is increased, the film is easily stretched to cause a dimensional change. Therefore, when printing the first color and the second and subsequent colors, the pattern is shifted and high-definition printing cannot be performed. There is also a disadvantage.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve these problems of the prior art. That is, an object of the present invention is to provide a method for producing a multilayer resin stretched film having high surface strength, excellent embossability, and good ink adhesion. Another object of the present invention is to provide a method for producing an inexpensive multilayer resin stretched film which is excellent in backing workability and can be effectively used as a building decoration material or the like. Further, the present invention has an object to solve the problem of providing a method for producing a stretched multilayer resin film which does not cause environmental pollution and does not deteriorate the incinerator during waste treatment.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, by controlling the melting point and the stretching temperature of the thermoplastic resin used for the multilayer resin stretched film, the present invention has been developed. The present inventors have found that a multilayer resin stretched film having excellent properties meeting the purpose of the present invention can be manufactured, and the present invention has been completed.

That is, the present invention relates to
On the surface of the base layer (A) containing 5% by weight and 60 to 15% by weight of an inorganic or organic fine powder, the base layer (A)
30 to 90% by weight of a thermoplastic resin having a melting point lower than that of the thermoplastic resin by 10 ° C. or more, and 70 to 10% by weight of an inorganic or organic fine powder having an average particle diameter smaller than that of the inorganic or organic fine particles of the base layer (A). % Of the surface layer (B) containing the thermoplastic resin of the surface layer (B).
An object of the present invention is to provide a method for producing a multilayer resin stretched film including a step of stretching at a temperature lower than or equal to ° C.

[0008] In a preferred embodiment of the present invention, the thermoplastic resin 30 to 30 is coated on the back surface of the base material layer (A) before stretching.
A step of forming a back layer (C) containing 70% by weight and 70 to 30% by weight of inorganic fine powder is further performed. Also,
After stretching, the surface layer (B) may be embossed. The stretching is desirably uniaxial stretching, and is preferably performed under the condition that the porosity of the multilayer resin stretched film calculated by the formula (1) is in the range of 5 to 60%.

[0009]

(Equation 2) ρ0: True density of stretched multilayer resin film ρ1: Density of stretched multilayer resin film

The average particle diameter of the inorganic or organic fine powder of the base layer (A) is in the range of 0.6 to 3 μm, and the average particle diameter of the inorganic or organic fine powder of the surface layer (B) is 0.1 to 2 μm.
The average particle diameter of the inorganic or organic fine powder of the back surface layer (C) can be preferably set in the range of 0.6 to 3 μm. Further, it is preferable to use an inorganic fine powder whose surface is subjected to a hydrophilic treatment for the back surface layer (C). As the thermoplastic resin of the base layer (A), the surface layer (B) and the back layer (C), a polyolefin resin, an olefin thermoplastic elastomer, or a mixture of a polyolefin resin and an olefin thermoplastic elastomer is used. be able to. A mixture of a polyolefin resin and an olefin thermoplastic elastomer is a polyolefin resin 1
It is preferable that the olefinic thermoplastic elastomer be contained in an amount of 5 to 100 parts by weight with respect to 00 parts by weight.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. The method for producing a stretched multilayer resin film of the present invention includes at least a step of forming a surface layer (B) on the surface of a base material layer (A) and a step of stretching the formed laminate.

[0012]Laminate forming process  In a preferred embodiment of the present invention, the base material layer is provided before the stretching step.
A back surface layer (C) is formed on the back surface of (A). Back layer (C)
Is formed before forming the surface layer (B) on the base material layer (A).
May or may not be. In some cases,
A surface layer (B) and a back layer (C) on both sides of the layer (A) at the same time
It may be formed. Base material layer formed by the production method of the present invention
(A), the surface layer (B) and the back layer (C)
Contains thermoplastic resin and inorganic or organic fine powder
You.

The type of the thermoplastic resin used for the base layer (A), front layer (B) and back layer (C) is not particularly limited. For example, polyolefin resin; polyamide resin such as nylon-6, nylon-6,6, nylon-6, T; heat of polyethylene terephthalate or a copolymer thereof, polybutylene terephthalate or a copolymer thereof, or aliphatic polyester. Plastic polyester-based resin; polycarbonate, atactic polystyrene, syndiotactic polystyrene and the like can be used.

Among them, it is preferable to use a non-polar polyolefin resin. Examples of the polyolefin resin include ethylene, propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, and 4-methyl-1.
-Carbon number 2 such as pentene and 3-methyl-1-pentene;
And a copolymer of 2 to 5 kinds of these α-olefins. The copolymer may be a random copolymer or a block copolymer.
Specifically, the density is 0.89 to 0.97 g / cm ³ , and the melt flow rate (190 ° C., 2.16 kg load) is 1 to
Branched polyethylene, linear polyethylene at 10 g / 10 min; propylene homopolymer having a melt flow rate (230 ° C., 2.16 kg load) of 0.2 to 8 g / 10 min;
Propylene / ethylene copolymer, propylene / 1-butene copolymer, propylene / ethylene / 1-butene copolymer, propylene / 4-methyl-1-pentene copolymer,
Propylene / 3-methyl-1-pentene copolymer, poly (1-butene), poly (4-methyl-1-pentene),
A propylene / ethylene / 3-methyl-1-pentene copolymer is exemplified. Among them, propylene homopolymer, propylene / ethylene random copolymer, and high-density polyethylene are preferable because they are inexpensive and have good moldability.

For the base material layer (A), the surface layer (B) and the back surface layer (C), a thermoplastic elastomer can be particularly selected and used as the thermoplastic resin. As used herein, the term “thermoplastic elastomer” includes both a rubber component having elasticity in a molecule (soft segment) and a molecular constraint component (hard segment) for preventing plastic deformation. While the hard segment acts as the point of flow of the flowable rubber and exhibits rubber-like properties, the hard segment is melted by heating to exhibit flow characteristics as a thermoplastic resin. In the present specification, other thermoplastic resins are referred to as “thermoplastic non-elastomers”.

A large number of thermoplastic elastomers having different types, molecular weights, arrangements, and the like of soft segments and hard segments are known. For example, examples of the styrene-based thermoplastic elastomer include Tuftec (trade name) manufactured by Asahi Kasei Kogyo Co., Ltd. and Lavalon (trade name) manufactured by Mitsubishi Chemical Corporation. Examples of the olefin-based thermoplastic elastomer include Mirastomer (trade name) manufactured by Mitsui Petrochemical Industries, Ltd. and Thermolan (trade name) manufactured by Mitsubishi Chemical Corporation.
As polyester-based thermoplastic elastomer, Toray
Hytrel (trade name) manufactured by DuPont, Toyobo
There is Pelprene (trade name). In addition, polyurethane thermoplastic elastomers and the like are known.

For the base material layer (A), the surface layer (B) and the back surface layer (C), one of the above-mentioned thermoplastic resins may be selected and used alone. At least one species may be selected and used in combination. When two or more kinds are used in combination, it is preferable to use a mixture of a thermoplastic non-elastomer and a thermoplastic elastomer. The mixing ratio is preferably 5 to 100 parts by weight of the thermoplastic elastomer per 100 parts by weight of the thermoplastic non-elastomer. Particularly, the blending amount of the thermoplastic elastomer is 5 to 50 parts by weight in the base layer (A) and 20 to 100 parts by weight in the surface layer (B).
In terms of parts by weight, the amount of pores in the base material layer (A) is
It is preferable because the content can be increased to improve embossability, printability, and surface strength of the surface layer (B).

The same thermoplastic resin or different thermoplastic resins may be used for the base layer (A), the surface layer (B) and the back layer (C). The thermoplastic resin can be appropriately selected according to the properties required for each layer. In order to use it as an architectural decoration material or the like, the surface layer (B) is often subjected to various types of printing, and then to a processing such as embossing. For this reason,
The surface layer (B) is required to have high-definition printability by various printing methods and ink adhesion strength capable of preventing ink dropout during embossing. In order to sufficiently meet these requirements, the surface layer (B) has a melting point 10 times higher than that of the base material layer (A).
Use a thermoplastic resin that is lower than ℃. The melting point of the thermoplastic resin used for the back layer (C) is not particularly limited, and may be the same as the melting point of the thermoplastic resin of the base layer (A) or the surface layer (B). May be different from the melting point of.

The kind of the organic or inorganic fine powder used for the base material layer (A), the surface layer (B) and the back layer (C) is not particularly limited. Examples of the inorganic fine powder include heavy calcium carbonate, light calcium carbonate, clay, talc, titanium oxide, barium sulfate, zinc oxide, magnesium oxide, diatomaceous earth, and silicon oxide. Of these, heavy calcium carbonate, clay, and diatomaceous earth are preferred because they are inexpensive and have good porosity during stretching.

Examples of the organic fine powder include polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, polyethylene naphthalate, polystyrene, melamine resin, polyethylene sulphite, polyimide, polyethyl ether ketone, polyphenylene sulphite and the like. Among them, it is preferable to use incompatible fine powder having a melting point higher than that of the thermoplastic resin to be used from the viewpoint of pore formation.

For the base material layer (A), the surface layer (B) and the back surface layer (C), one of the above fine powders may be selected and used alone, or two of them may be used alone. The above may be selected and used in combination. When two or more kinds are used in combination, an organic fine powder and an inorganic fine powder may be mixed and used. Further, the same fine powder or different fine powders may be used for the base material layer (A), the surface layer (B) and the back layer (C). However, as the fine powder of the surface layer (B), a powder having an average particle diameter smaller than that of the fine powder of the base material layer (A) is selected. By adjusting the average particle diameter in this way, surface protrusions after stretching are reduced, and the surface smoothness and the like are improved, and as a result, printing with higher definition can be performed.

The preferable range of the average particle size of the fine powder used in the base material layer (A) is 0.6 to 3 μm. If the average particle diameter is 0.6 μm or more, more sufficient voids (voids) can be formed by stretching. If the average particle size is 3 μm or less, the pores can be controlled to an appropriate size, and the occurrence of wrinkles in the film can be more effectively prevented. The preferable range of the average particle diameter of the fine powder used for the surface layer (B) is 0.1 to 2 μm. By setting the average particle diameter within the above range, fine cracks can be formed on the surface to improve the adhesiveness of the ink, and white spots during printing can be more effectively prevented. Further, in the surface layer (B), the content of coarse particles having a particle diameter of 44 μm or more which causes surface projections of the multilayer resin stretched film is preferably set to 10 ppm or less.

The preferable range of the average particle size of the fine powder used for the back layer (C) is 0.6 to 3 μm for the same reason as that for the fine powder of the base material layer (A). However, it is preferable to use an inorganic fine powder whose surface has been subjected to a hydrophilic treatment for the back surface layer (C). The hydrophilization treatment can be performed by treating the inorganic compound with a water-soluble anionic or cationic or nonionic polymer surfactant having an average molecular weight of 1,000 to 150,000 when wet-milling. In addition, it can also be carried out by treating the inorganic compound with an anion, a cation or a non-ionic antistatic agent during wet pulverization. Both of these processes may be performed in two stages. Preferred examples of the hydrophilized inorganic fine powder include those described in JP-A-7-300568.

The above two-stage treatment is carried out by applying an average particle diameter of 0.6 to 3
The use of the hydrophilic fine inorganic powder applied to the fine inorganic powder of μm makes it possible to adjust the contact angle (water contact angle) of the back surface layer (C) to water within a preferable range. The preferred range of the water contact angle is 10 to 80 °, and the more preferred range is 20 to 80 °.
70 °. If the contact angle with water is less than 10 °, the penetration rate of water becomes too high, and when an aqueous paste is used, the paste component itself permeates too much inside. For this reason, the amount of glue to be applied increases and the production cost increases. On the other hand, if the contact angle exceeds 80 °, the permeation rate of water is low and the drying property of the paste is low, so that the productivity is reduced and the production cost is increased. Further, since the permeation of the adhesive component itself is small, the adhesiveness between the adhesive and the stretched multilayer resin film is also reduced. In addition, the water contact angle in this specification shows what was measured using the contact angle meter (Kyowa Interface Chemical Co., Ltd. make, model CA-D).

As described above, by using the inorganic fine powder subjected to the hydrophilic treatment for the back layer (C) and improving the wettability with water, the adsorbability of the aqueous adhesive or the like to the back layer (C) is improved. And drying properties are improved. Further, by using the inorganic fine powder treated with the antistatic agent, the back surface layer (C) can be provided with an antistatic property. Therefore, it is possible to obtain a stretched multilayer resin film which is free from charging trouble at the time of applying an adhesive or a pressure-sensitive adhesive such as a backing and has excellent drying properties and excellent adhesiveness.

In the production method of the present invention, each layer is formed by mixing the thermoplastic resin and the fine powder. In the base material layer (A), 40 to 85% by weight of a thermoplastic resin and 60 to 15% by weight of an inorganic or organic fine powder are blended. If the amount of the fine powder exceeds 60% by weight, it is difficult to form a multilayer resin stretched film having a uniform thickness, and if the amount is less than 15% by weight, the amount of pores formed by stretching is small, so that embossability is poor. turn into.

In the surface layer (B), a thermoplastic resin is used in an amount of 30 to
90% by weight, and 70 to 10% by weight of inorganic or organic fine powder. When the amount of the fine powder exceeds 70% by weight, it is difficult to uniformly stretch the film, and the surface film of the produced multilayer resin stretched film is liable to be cracked, which is not practical. If the amount of the fine powder is less than 10% by weight, ink adhesion will be poor. In the back surface layer (C), 30 to 70% by weight of a thermoplastic resin and 70 to 30% by weight of an inorganic or organic fine powder are blended. If the amount of the fine powder exceeds 70% by weight, it becomes difficult to form a multilayer resin stretched film having a uniform thickness. In particular, the inorganic fine powder subjected to the hydrophilization treatment is preferably used in an amount of 10% by weight or more for exhibiting hydrophilicity.

When the fine powder is mixed and kneaded in the thermoplastic resin, a dispersant, an antioxidant, a compatibilizer, a flame retardant, an ultraviolet stabilizer, a coloring pigment, and the like can be added as necessary. In particular, it is preferable that the base layer (A) and the surface layer (B) are colored to a desired color by using an inorganic or organic coloring pigment. When a stretched multilayer resin film is used as a durable material, it is preferable to add an antioxidant, an ultraviolet stabilizer, and the like. Furthermore, when an organic fine powder is used, the type and amount of the compatibilizer are important because they determine the particle form of the organic fine powder. Preferred examples of the compatibilizer include maleic acid-modified polypropylene (trade name: Umex, manufactured by Sanyo Chemical Industries, Ltd.). Further, the amount of the compatibilizer to be added is 10 g of the organic fine powder.
The amount is preferably 0.5 to 10 parts by weight with respect to 0 parts by weight.

A laminate is prepared using a blend containing a thermoplastic resin, fine powder and other additional components.
The thickness of each layer of the prepared laminate is as follows: surface layer (B) / base layer (A) / backside layer (C) = (1-3) / (8-4) / (1)
It is preferable to prepare so as to satisfy (3). By setting the thickness of each layer in this range, a multilayer resin stretched film having excellent surface strength, printability, embossability, and emboss return can be obtained. When the thickness configuration of the base material layer (A) is 4 or less, it is not preferable because embossing is deteriorated.

[0030]Stretching process  Low number of substrate layer (A), surface layer (B) and back layer (C)
The laminate comprising at least three layers is then subjected to a stretching step. 3 layers
According to the present invention, the three layers are separately formed.
Simple and inexpensive multilayer resin compared to the case where it is stretched into individual pieces and laminated
Stretched films can be produced. In addition, the present invention
According to the manufacturing method, the base layer (A) and the surface layer (B) are formed.
The control of the holes to be formed becomes easier. In particular, the base material layer (A)
Has more pores formed by stretching than the surface layer (B).
So that the base material layer (A) improves the embossing suitability
It is preferable to function effectively as a possible layer.

For stretching, various known methods can be used. The stretching temperature may be set to be equal to or higher than the glass transition temperature of the thermoplastic resin to be used in the case of the non-crystalline resin, or to be equal to or lower than the melting point of the crystal part in the case of the crystalline resin. it can. The stretching temperature is lower than the melting point of the thermoplastic resin of the surface layer (B) by 5 ° C. or more and 15 ° C. or lower than the melting point of the thermoplastic resin of the base layer (A). If the temperature is not set in this manner, the sheet sticks to the roll surface, especially when stretching between rolls is performed, and a sticking pattern appears on the multilayer resin stretched film surface.
Further, the number of cracks formed in the surface layer (B) is reduced, so that the ink adhesion is reduced.

Specific examples of the stretching method include inter-roll stretching using a peripheral speed difference between roll groups, and clip stretching using a tenter oven. Among them, uniaxial roll stretching is preferable because the stretching ratio can be arbitrarily adjusted and the size and number of pores formed can be controlled. In particular, by uniaxially stretching all the layers, holes and cracks are formed in the shape of a football, so that a larger number of fine holes can be formed than in biaxial stretching. In addition, since the resin is stretched and oriented in the flow direction of the film, it is possible to obtain a multilayer resin stretched film having higher tensile strength and less dimensional change due to tension during printing or processing than a non-stretched film.
Furthermore, since the orientation of the resin is less than in biaxial stretching,
A multilayer resin stretched film having good resistance to emboss return can be obtained.

The stretching ratio is not particularly limited, and is appropriately determined in consideration of the purpose of use of the stretched multilayer resin film and the properties of the thermoplastic resin used. For example, when a propylene homopolymer or a copolymer thereof is used as the thermoplastic resin, when the film is stretched in one direction, the ratio is about 1.2 to 12 times, preferably 2 to 7 times. Further, heat treatment at a high temperature is performed as necessary. The stretching speed is preferably from 20 to 350 m / min.

The produced multilayer resin stretched film has a porous structure having fine pores, and the above formula (1)
Is preferably in the range of 5 to 60%. If the porosity is less than 5%, embossing tends to be poor. On the other hand, if the porosity exceeds 60%, the material strength of the film is reduced, and the surface tends to be easily broken by cellophane tape or the like. Further, it is preferable that the porosity of each layer satisfies the relationship of surface layer (B) <base layer (A) <back layer (C). While not being bound by any theory, by satisfying such porosity conditions, it becomes possible to absorb the thermal deformation of the resin portion that occurs during embossing, and to improve the embossability and return resistance. Is considered to be good. Also,
Since fine cracks are formed in the surface layer (B), printability is improved.

In formula (1), ρ0 represents the true density of the stretched multilayer resin film or each layer, and ρ1 represents the density of the stretched multilayer resin film or each layer. Unless the material before stretching contains a large amount of air, the true density is approximately equal to the density before stretching. The density of the multilayer resin stretched film is 0.60
It is preferably in the range of 〜1.20 g / cm ³ .

The stretched multilayer resin film produced by the production method of the present invention may be used as it is,
It may be used by being laminated on another thermoplastic film or the like. When further laminating, it can be laminated on a transparent or opaque film such as a polyester film, a polyamide film and a polyolefin film. The thickness of the multilayer resin stretched film is not particularly limited.
For example, 30 to 400 μm, preferably 60 to 200 μm
m. Further, by laminating the film with another film as described above, the overall thickness can be reduced to about 1 mm.

The produced multilayer resin stretched film can be used for various applications. For example, it is useful for wallpaper for architectural decoration, decorative paper for decorative plywood, flooring, interior materials for automobiles, tack labels that have been subjected to adhesive processing, and the like.

The surface layer (B) of the stretched multilayer resin film can be printed according to the purpose of use. The type and method of printing are not particularly limited. For example, printing can be performed using a known printing means such as gravure printing using an ink in which a pigment is dispersed in a known vehicle, aqueous flexo, silk screen, UV offset rotary printing, or the like. In addition, printing can be performed by metal deposition, gloss printing, mat printing, or the like. The pattern to be printed can be appropriately selected from natural patterns such as stones, wood, lattices, polka dots, and floral patterns, abstract patterns, characters, and the like.

The multilayer resin stretched film can be embossed. Embossing is generally performed after printing, but printing may be further performed after embossing. The embossing can be performed, for example, by using a known various press such as a lithographic press, a roll embossing machine, or an embossing machine to shape the concavo-convex shape of the embossing plate by heat or pressure. The roll embossing method is a method in which the concavo-convex shape of a cylindrical embossing plate is formed on a target material by hot pressing. The hot pressing is performed by heating the resin used for the surface layer (B) of the multilayer resin stretched film between the heat deformation temperature and the melting temperature, and pressing the embossing plate against the surface of the multilayer resin stretched film. After shaping, cooling is performed to fix the shape. As the heating method, for example, a method such as infrared irradiation, hot air blowing, conduction heat from a heating roller, dielectric heating, or the like is used. It should be noted that embossing can be performed simultaneously with film formation before or after stretching without using an embossing machine.

When the stretched multilayer resin film is used as a decorative plywood, the design can be improved by wiping after embossing and filling the recess with wiping ink. In particular, it is suitable for reproducing the appearance of the conduit portion of the grain.

It is desirable to form a surface protective layer made of a transparent resin layer on the outermost layer. The surface protective layer has a function of protecting the surface layer and imparting a three-dimensional effect to the design such as a pattern or emboss of the lower layer. Therefore, the surface protective layer is particularly useful when the multilayer resin stretched film is used as a decorative board or wallpaper. The surface protective layer can be formed by coating or bonding. In order to further improve the surface physical properties, it is preferable to use a colorless transparent or colored transparent resin having excellent surface physical properties such as weather resistance, abrasion resistance and stain resistance. Preferred as such a resin are, for example, various liquid acrylates, polyesters and other ionizing radiation-curable resins, two-component curable resins such as polyurethanes and unsaturated polyesters, fluororesins, polysiloxane resins and the like.
The surface protective layer may contain known antibacterial agents, antifungal agents, fragrances and the like.

Other materials can be attached to the back surface of the multilayer resin stretched film which has been subjected to various printing and embossing processes. For example, when used as wallpaper or flooring, backing paper or the like can be attached. The material used for the backing is not particularly limited, for example, thin paper, paper such as kraft paper, inorganic fiber such as glass fiber and carbon fiber, woven fabric, nonwoven fabric, resin film or sheet, metal foil, and simple substance such as woody material. Alternatively, a composite material obtained by laminating the above materials by a known means such as adhesion or heat fusion can be used.

Further, a laminated resin stretched film can be manufactured by laminating a multi-layer stretched resin film on a metal plate such as an iron plate or an aluminum plate by using an adhesive or heat fusion, for example, to produce a resin decorative plate lined with a plate-like material. Further, a resin decorative plywood can be manufactured by laminating a multilayer resin stretched film on various types of wood plywood with an adhesive. Furthermore, the pressure-sensitive adhesive layer on the backing, or the pressure-sensitive adhesive layer and a release sheet are laminated and formed,
Tack seal type wallpaper can also be manufactured.

[0044]

The present invention will be described more specifically with reference to the following Examples, Comparative Examples and Test Examples. The materials, usage amounts, ratios, operations, and the like shown below can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples. The materials used are summarized in the table below. In addition, MFR in a table | surface means a melt flow rate.

[0045]

[Table 1]

(Examples and Comparative Examples) According to the following procedures, a method for producing a multilayer resin stretched film of the present invention (Examples 1 to 5) and a comparative production method (Comparative Examples 1 to 3)
Was carried out, and wallpaper was produced using the films produced by these methods. Table 2 summarizes the types and amounts of materials used in the production of each film, the stretching conditions, and the states of the produced films. Formulations [A], [B] and [C] were prepared by mixing thermoplastic resin, elastomer and fine powder. These compounds were melt-kneaded with three extruders set at 250 ° C., respectively, and the compound [B] was laminated on the front side of the compound [A] and the compound [C] was laminated on the back side in a die. Then, the resultant was extruded and cooled to 70 ° C. by a cooling device to obtain a three-layer unstretched sheet. After heating this sheet to a predetermined temperature, it was stretched at a predetermined ratio between rolls in the longitudinal direction. Then, a discharge treatment machine (manufactured by Kasuga Electric Co., Ltd.) is provided on both sides of the obtained stretched film.
Was used to perform a corona treatment of 50 W / m ² · min to obtain a stretched multilayer resin film having a three-layer structure. The porosity of each layer of the obtained stretched multilayer resin film, the overall porosity, the thickness and the density were as shown in Table 2.

Next, gravure printing of a floral pattern (ink: manufactured by Toyo Ink Co., Ltd., trade name: “CCST”) was applied to the surface layer (B) of the stretched multilayer resin film, and then 100 ° C.
Was embossed with a heated embossing roll. Further, a UV curable resin (manufactured by Dainichi Seika) was applied on the surface so as to be 3 g / m ^2, and a high-pressure mercury lamp (8
(0 W, 10 m / min). Furthermore, 5 g of a water-soluble starch-based paste is applied to the back layer (C) of the multilayer resin stretched film.
/ M ² using a roll coater, and 8
After performing a drying treatment in a dryer set at 0 ° C., a release paper was backed to produce a wallpaper.

[0048]

[Table 2]

(Test Example) The following tests and evaluations were performed on the produced multilayer stretched resin film and wallpaper.

1) Embossability (hanging) The embossing formed on the surface of the wallpaper was visually observed and evaluated according to the following criteria. ：: Three-dimensional effect and sharpness △: Slightly lacking sharpness but three-dimensionality, no problem in practical use ×: Neither depth nor sharpness. Unavailable for practical use

2) Emboss return resistance The backing paper of the wallpaper was removed, and an appropriate amount of water was applied to the starch paste-coated surface with a brush, and the resultant was adhered to the surface of the plywood to prevent air from entering, thereby obtaining a wall plate. Immediately superimpose the two wall plates so that the surfaces on which the wallpapers are stuck are in contact with each other, and place them in a dryer at 60 ° C. for 30 minutes.
A pressurization of 0 kg / m ² was performed for 3 minutes. Thereafter, the wallboard was taken out, and the state change of the emboss was visually observed and evaluated according to the following criteria. ：: No change ：: The three-dimensional effect was slightly reduced, but there was no problem in practical use. Chipping, apparent embossing return, and practical problem x: Emboss is almost completely lost and cannot be used practically

3) Adhesiveness of ink on surface layer (B) Adhesive tape (trade name "Cellotape" manufactured by Nichiban Co., Ltd.) is applied to the surface of the gravure-printed wallpaper and pressed sufficiently. The film was peeled off at a constant speed in a direction at 90 degrees to the adhesive surface. The manner in which ink was removed from the wallpaper surface was visually observed and evaluated according to the following criteria. ：: The ink was not peeled at all. ○: The material portion of the film was destroyed, but there was no problem in practical use. ：: Tape There is resistance at the time of peeling, but most of the ink is peeled off, and there is a problem in practical use.
Unavailable for practical use

4) Surface Strength of Surface Layer (B) An adhesive tape (trade name “Cellotape” manufactured by Nichiban Co., Ltd.) was applied to the surface layer (B) of the multilayer resin stretched film, and pressed sufficiently with a finger. Use a tensile tester (manufactured by Shimadzu Corporation: trade name "Autograph") to apply 100
Peeling was performed at a speed of 0 mm / min. The state change of the surface layer (B) after peeling was observed with the naked eye and evaluated according to the following criteria. 変 化: No change ：: Very slight fluffing of the surface, but no problem in practical use △: Many fluffing of the surface There is a problem in practical use. ×: Peeling occurs from inside the film layer, and it cannot be used practically.

5) Water contact angle of back surface layer (C) The contact angle of the back surface layer (C) of the multilayer resin stretched film was measured using a contact angle meter (made by Kyowa Interface Chemical Co., Ltd .: Model CA- D).

6) Paste Drying Property of Back Layer (C) Starch paste (manufactured by Tokiwa Chemical Co.) is coated on the back layer (C) of the stretched multilayer resin film using a rod bar so that the solid content is 5 g / m ^2. Then, the time required for the coated starch paste to change its surface gloss was measured.

7) Adhesive Adhesion of Backside Layer (C) Adhesive tape (trade name “Cellotape” manufactured by Nichiban Co., Ltd.) is applied to the dried coated surface of the starch paste of 6), and after sufficiently pressing, the adhesive is applied. The tape was peeled off at a constant speed in a direction at 90 degrees to the adhesive surface. The manner in which the glue was removed was visually observed and evaluated according to the following criteria. ：: The adhesive is cohesively broken. ○: The material portion of the film is destroyed. ：: There is resistance when the tape is peeled off, but the glue is partially peeled off from the back layer (C), and there is a practical problem. X: Tape peeling Occasionally there is no resistance and the entire amount of glue peels off from the back layer (C), making it impractical

The results of the above tests are summarized in the following table. In the table, the difference between the melting point of the thermoplastic resin of the surface layer (B) and the stretching temperature (temperature difference X) and the melting point of the thermoplastic resin of the base layer (A) and the heat of the surface layer (B) are shown. The difference from the melting point of the plastic resin (temperature difference Y) is also described.

[Table 3]

As is clear from Table 3, the multilayer resin stretched film produced by the production method of the present invention has an embossing property, an emboss return resistance, an ink adhesion and a surface strength of the surface layer (B), and a back surface layer (C). ) Are good in water contact angle, glue drying property and glue adhesion (Examples 1 to 5)
5). On the other hand, when the stretching is performed at a temperature that does not satisfy the condition that the melting point of the thermoplastic resin of the surface layer (B) is 5 ° C. or more, or when the stretching is not performed,
The properties of the produced film are inferior and not practical.

[0059]

According to the method for producing a stretched multilayer resin film of the present invention, it is possible to provide a stretched multilayer resin film excellent in printing suitability, embossability, and backing suitability, and having high surface strength. . Therefore, according to the present invention, it is possible to effectively produce a multilayer resin stretched film that can be used for various uses including architectural decorative materials.

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Claims (9)

[Claims] 1. The surface of a substrate layer (A) containing 40 to 85% by weight of a thermoplastic resin and 60 to 15% by weight of an inorganic or organic fine powder, A surface layer containing 30 to 90% by weight of a thermoplastic resin having a melting point of 10 ° C. or lower and 70 to 10% by weight of an inorganic or organic fine powder having an average particle diameter smaller than that of the inorganic or organic fine particles of the base layer (A). A method for producing a multilayer resin stretched film, comprising: forming (B) and stretching at a temperature lower by at least 5 ° C. than the melting point of the thermoplastic resin of the surface layer (B). 2. A backside layer (C) containing 30 to 70% by weight of a thermoplastic resin and 70 to 30% by weight of an inorganic fine powder is formed on the backside of the base layer (A) before performing the stretching. The method for producing a stretched multilayer resin film according to claim 1, further comprising a step. 3. The method for producing a stretched multilayer resin film according to claim 1, further comprising a step of embossing the surface layer (B) after the stretching. 4. The stretching according to claim 1, wherein the stretching is uniaxial stretching.
4. The method for producing a stretched thermoplastic resin film according to any one of items 1 to 3. 5. The method according to claim 1, wherein the stretching is performed under the condition that the porosity of the stretched multilayer resin film calculated by the formula (1) is in the range of 5 to 60%. A method for producing a stretched thermoplastic resin film. (Equation 1) ρ0: True density of stretched multilayer resin film ρ1: Density of stretched multilayer resin film 6. The inorganic or organic fine powder of the base layer (A) has an average particle size of 0.6 to 3 μm, and the inorganic or organic fine powder of the surface layer (B) has an average particle size of 0.6 to 3 μm. Is in the range of 0.1 to 2 μm, and the average particle diameter of the inorganic or organic fine powder of the back layer (C) is in the range of 0.6 to 3 μm. A method for producing a stretched multilayer resin film. 7. The method for producing a stretched multilayer resin film according to claim 1, wherein the back surface layer (C) contains an inorganic fine powder whose surface is subjected to a hydrophilic treatment. 8. The thermoplastic resin of the base layer (A), the surface layer (B) and the back layer (C) is a polyolefin resin, an olefin thermoplastic elastomer, or a polyolefin resin and an olefin heat. The method for producing a multilayer resin stretched film according to any one of claims 3 to 7, which is a mixture with a plastic elastomer. 9. The mixture according to claim 8, wherein the mixture of the polyolefin resin and the olefin thermoplastic elastomer contains 5 to 100 parts by weight of the olefin thermoplastic elastomer based on 100 parts by weight of the polyolefin resin. Method for producing a multilayer resin stretched film.