JPS59198149A - Composite film and manufacture of decorative polystyrene foamd body by using said film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite film suitable for applying a sample on the surface of a polystyrene foam, and a polystyrene foam that is printed on the surface of this composite film and decorated using a decorative material such as a blank or a label. The present invention provides a method for manufacturing a body.

Foamed polystyrene molded products are used in electric washing machines, televisions,
Trenches are used as cushioning and packaging materials for home appliances such as refrigerators.
It is used as a cup for coffee and tea on Shinkansen trains and on airplanes.

When used as the former cushioning material, a cardboard box is also used to package the cushioning material, and the product name, manufacturer's age, sales name, etc. are printed on the cardboard box. [7 or 17 However, the use of cardboard boxes increases the cost of packaging materials, so it is recommended not to use cardboard boxes or use 1
However, there is a desire for packaging materials that can be used in pieces, rather than in the form of boxes.

In addition, in the case of the latter cup-shaped container, an adhesive label is rarely seen attached, but the appearance of this container is poor. Historically, high-quality instant cup noodles have been sold, but in order to differentiate them from the conventional inexpensive popular cup noodles, more sophisticated decorations were added to the expanded polystyrene containers. The reality is that it is being considered.

It has been known for a long time to paint plastic molded products with decorative sheets such as label blanks. for example,
Cut out thermoplastic resin films such as polyvinyl chloride, polypropylene, polyethylene, etc. printed with letters and designs [~
This is fixed in a mold by electrostatic adhesion or reduced pressure, then a melted thermoplastic resin of the same material as the film is brought into contact with the film under pressure or reduced pressure F, and the melted material is further cooled to form a label. A method for manufacturing thermoplastic synthetic resin molded products with pasted and painted images has been proposed (Japanese Patent Publication No. 1983-
No. 5036, No. 38-26119, No. 40-1298
No. 8, No. 46-9959, No. 4B-12865, etc.).

For injection-molded products, blow-molded products, vacuum-formed products, etc. that use printed thermoplastic resin films as labels, the label is attached during molding, so the adhesion between the label and the molded product is strong. be. In addition, when the material of the label is made of thermoplastic resin film with high water resistance, it is especially useful as a liquid hollow container for detergents, shampoos, antifreeze, medicine bottles, etc.

The present inventors applied these painting methods to molded products made of foamed polystyrene in order to eliminate the use of cardboard boxes or to decorate cup-shaped containers. ' Impact polystyrene interleaving paper (Special Publication 1973-1983)
No. 20, Japanese Patent Publication No. 49-43115), and printed on the surface of synthetic paper made of a stretched film of a resin composition made of high-impact polystyrene mixed with an inorganic filler such as calcium carbonate, and fixed in a mold as a blank. let me,
Next, the pre-foamed beads are placed in the mold,
When we produced foamed polystyrene molded products with these printed synthetic papers laminated on the surface by heat molding at 0°C, the synthetic paper melted during molding! 7. It was found that the printing was slightly peeled off. Yes, when the synthetic paper is thick, such as 60 microns or 150 microns, the blank may curl while the product is being stored. The phenomenon of peeling from the foam product was also observed.

The inventors determined that the cause of this problem was due to the fact that the resin material of the decorative film and the molded product were the same polystyrene, and the molding temperature.
Synthetic paper (2-way stretched film) is made by blending fine inorganic powder with crystalline thermoplastic resins such as polypropylene, polyethylene terephthalate, and polyamide, which have a melting point higher than the molding temperature of polystyrene (110 to 120°C).
Special Publication No. 46-40794, USP 3,741,841
No., USP No. 4,318,950, Japanese Unexamined Patent Publication No. 1983-118
．． No. 437 and No. 56-141, 339), it was found that the fusion between the foamed polystyrene product and the synthetic paper was insufficient.

In order to resolve the poor thermal welding of these synthetic papers on which delicate letters and designs can be printed in multicolor offset, the present inventors have further investigated various types of decorative films7, and have developed a synthetic paper made of these high-melting point resins. On the back side of the paper, the wall thickness is 1 to 2 mm. The film has a multi-layer structure in which 6 layers of 0 micron polystyrene film are glued together, and can be used for gravure printing, flexographic printing, and offset printing. ), that is, even when used as a makeup sheet,
It has been discovered that it is possible to obtain painted foamed polystyrene molded products with no blurred print and strong fusion bonding.
The present invention was achieved17.

That is, the first aspect of the present invention is that the inorganic fine powder is contained in an amount of 8 to 65% by weight.
A stretched film of thermoplastic resin containing a melting point of 145° C. or higher is used as a paper-like layer 17, and a polystyrene film with a wall thickness of 1 to 0 microns constitutes the surface opposite to this paper-like layer.
b Th ) It provides a composite film having at least a two-layer structure with a 1% layer.

The second aspect of the present invention is to form a stretched film of a thermoplastic resin containing 8 to 65% by weight of inorganic fine powder and having a melting point of 145° C. or higher as a paper-like layer. A blank or a decorative sheet for a label is made of a male mold and a female mold by printing on the paper-like layer side of a composite film having at least a two-layer structure with a polystyrene film having a wall thickness of 1 to 30 microns as the back layer. The decorative material is fixed to the inside of at least one side of the mold so that the paper-like layer side is in contact with the mold, and then the mold cavities of the mold are filled with pre-expanded polystyrene beads, and then steam is introduced into the mold cavities (17). To provide a method for producing a decorated polystyrene foam, which is characterized by fusing beads together to form a foam and adhering the formed foam to a decorative sheet.

In the practice of the present invention, the simplest structure of the composite film for multi-layered labels and blanks before offset printing is such that the amount of inorganic filler is 8 to 65% by weight, preferably 20% by weight.
A stretched film of crystalline thermoplastic resin containing ~55% by weight is used as a paper-like layer, with a wall thickness of 1 to 30 microns (μ), preferably 5 to 20μ, and a density of 0.93 to 1.07 f”CC.
The wall thickness is 30 to 300μ with polystyrene as the back layer.
It is a composite film with a two-layer laminated structure with a suitable size of 35 to 100μ.

Such a composite film is made of, for example, polypropylene containing an inorganic filler, and an adhesive resin such as a metal salt (Na, K, Zn) of an ethylene/acrylic acid copolymer (Na, K, Zn) or a maleic anhydride grafted ethylene/vinyl acetate copolymer to the polystyrene. The 17 compositions were melted in separate extruders, mixed, fed into the same die, laminated in the die, coextruded into a sheet, cooled to 40-80°C,
Reheat to 64°C, preferably 145-160°C, and heat 35-10 times in the longitudinal and transverse directions, simultaneously or sequentially 2 times.
The stretched film obtained by axial stretching is 165~
It is obtained by annealing at 168° C. for 5 to 60 seconds.

In addition, a corona discharge treatment was applied to a film obtained by longitudinally stretching a polypropylene film containing an inorganic filler by 3.5 to 7 times at 134 to 155°C using the difference in circumferential speed between the roll groups. and apply isocyanate adhesive.
After drying with hot air, the polystyrene film is then dry laminated. In these methods for producing multilayer films as well as in the methods for producing composite films having three or more layers described below, after stretching, the corona discharge treatment and annealing treatment described above are performed as necessary.

When the composite film has three or more layers, it can be manufactured in various ways. For example, ■ polypropylene containing 8 to 65% by weight of inorganic fine powder, ω), metal salts of ethylene/acrylic acid copolymer ('KXNa, Zn) to polypropylene;
), a composition containing 0.5 to 50% by weight of an adhesive resin such as maleic anhydride kraft polyethylene or polypropylene, C), and polystyrene were each melted and kneaded using separate extruders.1. The melt is transferred to one die 7, and inside the die, a film consisting of Q3) is laminated as an intermediate layer, and the coextruded laminated sheet is simultaneously heated at a temperature lower than the melting point of the polypropylene (4). , or by sequential biaxial stretching. Also, the above [F])
After longitudinally stretching the polystyrene coextruded sheet of composition C) in advance, a sheet of the polypropylene composition of (4) is laminated on the surface side of the coextruded sheet of Q3).
1. ,, it can also be obtained by subsequent transverse stretching.

Furthermore, on each side of the sheet Q3) which had been longitudinally stretched in advance,
It can also be obtained by melt-laminating the polypropylene composition sheets of (1) and C) polystyrene sheets of (10) and then laterally stretching the sheets.

Furthermore, the polypropylene containing the inorganic fine powder of (A) is melt-laminated (7) on the front and back surfaces of the longitudinally stretched film of the material (S) above (7), and then this is horizontally stretched [7] to form the synthetic paper obtained. (This product is sold by Oji Yuka Synthetic Paper Co., Ltd. under the trade name Yubo FPL: TJ.) An isocyanate adhesive is applied to the back side of the paper, and then the polystyrene film (C) is latri-laminated. It is also manufactured by

In these embodiments, the film of the base layer (B) contains 55% by weight of inorganic fine powder, U, and 1 to 15 to 5 pieces of clay.
0% by weight may be 1;

Among these multilayer films, from the viewpoint of offset printability, it is preferable that the paper-like layer of polypropylene containing 8 to 65 layers of inorganic fine powder is oriented only in one axis direction. When stretched, cracks occur on the surface with the inorganic fine powder as the nucleus, resulting in good adhesion and drying properties of printing ink.8
When biaxially stretched, there are many opportunities for inorganic fine powder to be oriented, and deep cracks formed by -axis stretching may disappear due to stretching, resulting in poor offset printability. Inferior to oriented film.

Further, the number of layers is preferably three or more layers including a biaxially oriented polypropylene film layer as an intermediate layer. This biaxially oriented polypropylene film can give stiffness to the label, and the thickness of the composite film is 30 to 300 μm, preferably 45 μm, which facilitates paper feeding during sheet offset printing.
~100μ, and the thickness of the back layer is 1~30μ,
Preferably it is 5 to 20μ. If the thickness of the 61-glue film is thinner than 30 μm, paper feeding and offset printing will be difficult.

Additionally, the composite film may shrink during molding. If the wall thickness exceeds 300μ, it is economically disadvantageous. The thickness of the polystyrene film of the back layer needs to be 1 μm or more so that the polystyrene film is melted by the heat of steam during molding of the polystyrene foam and the molded product and the composite film are firmly bonded. Additionally, if it exceeds 20μ, the composite film will curl, making offset printing difficult.
1. is preferred because it becomes difficult to fix the composite film to the mold. <do not have.

In the following, polypropylene is used as the heat-containing resin of the composite film, and the resin and 12
Any crystalline thermoplastic resin with a melting point higher than that of polystyrene may be used, and propylene homopolymer (melting point t
6a-170℃) Propylene-ethylene copolymer (melting point 145-160℃), propylene-ethylene-pudenol 1 copolymer (melting point 145-160℃), propylene:/
・Propylene copolymers such as Zote/1 copolymer (melting point 145-158°C), polyethylene terephthalate (melting point 236-248°C), nylon 6 (melting point 246-252°C)
℃) etc. can also be used.

In addition, polystyrene has a density of 103 to 1.07S.
In addition to styrene homopolymer of '10♂, styrene/α-methylstyrene copolymer, styrene/methyl methacrylate copolymer, styrene/acrylonitrile copolymer, and 50% by weight or less of these resins, preferably 8 to 45% by weight %
Styrene/Buta 13 Diene copolymer rubber, low density polyethylene, isoprene rubber, high density polyethylene, ethylene/vinyl acetate copolymer, ethylene/(meth)acrylic acid copolymer are also L<
can be replaced with its gold M (Na, Zn) salt, ethylene/lower alkyl (meth)acrylate (C1-c8) ester copolymer, etc. Polystyrene containing 10 to 50% by weight of polyethylene or ethylene/vinyl acetate copolymer is sold by Mitsubishi Yuka Co., Ltd. under the trade name "Diemilon". Such things are
It is produced by supplying styrene monomer in which a polymerization initiator such as benzoyl peroxide is dissolved to a suspension of resin particles such as polyethylene dispersed in water, and carrying out suspension polymerization at 80 to 130°C for 6 to 18 hours. (Unexamined Japanese Patent Publication No. 52-50
No. 389, No. 52-50390, No. 49-85187
No. 49-97884).

The inorganic fine powder has a particle size of 15μ or less, preferably 0.
1-3μ heavy calcium carbonate, clay, titanium oxide,
Diatomaceous earth, kaolin, talc, etc. are used14-.

The composite film of the present invention is printed by off-seven printing, gravure printing, etc. on the paper-like layer side, and is used as a decorative sheet for the film with decorations for foamed polystyrene type products.

This decorative film is cut, cut out, and bent as necessary (especially when used as a blank), and placed in a mold using conventional electrostatic adhesion methods, vacuum methods, etc. so that the printed surface is in contact with the mold. fixed, then pre(+i
i1 After the foamed polystyrene foam particles are filled into the gap, they are heated with steam at 100 to 130°C to fuse the pre-expanded particles together and form polystyrene foam products and cosmetics by this fusion. Adhesion is carried out with a printed composite film, which is a sheet.

After cooling, the mold is opened and the product with the decorative sheet stuck to the surface of the polystyrene foam is taken out.

This mold foam molding is conventional polystyrene mold molding (Japanese Patent Publication No. 45-33316, British Patent No. 1,392.
No. 467, No. 1,409,285, USP 3,46
No. 1,088). However, the conventional method for obtaining a foamed polystyrene molded product encapsulated with a non-oriented polyethylene film (JP-A-53-94375;
4-46269).

The pre-expanded particles are obtained by pre-foaming expandable polystyrene particles with a particle size of 0.65-2 mm containing 3-10 g 1'% of an expanding agent such as furin-pentane, he-7-phosphorus, or dichlorodifluoroethane using steam. The bulk density is 0.01
5y/l -0.1y/l and particle size of 1 to 8 can be used. The material of these expandable polystyrene particles is not limited to styrene homopolymer, but also styrene/methyl methacrylate copolymer, styrene/α-
It may also be a methylstyrene copolymer. Also, part 5
0 weight percent or less, 8 to 50 weight percent of the weight ratio 12< may be replaced by polyethylene or ethylene/vinyl acetate copolymer. The latter is prepared in the same manner as the above-mentioned ``Gemilon'' except that it contains an expanding agent (
JP-A Nos. 48-101457, 50-127964, 50-127965, 51-37980, and 53-23358). Such monoke is sold by Yuka Verdissier Co., Ltd. under the trade name "Ellenpol" and by Sekisui Plastics Co., Ltd. under the trade name °°Biocelan.Using these pre-expanded particles containing polyethylene, etc. The shape recovery property of the resulting foam product after being subjected to a compressive load is better than that of a foam product obtained using pre-expanded particles that do not contain these polyethylene or the like.

If the composite film of the present invention is used as a decorative sheet for painting polystyrene foam, there will be no problems such as heat shrinkage, blurring of printing, curling, etc. even though stretched film is used, and polystyrene foam moldings will not be affected. The decorative sheet can be firmly attached to the surface.

Therefore, since this printed composite film (decorative sheet 17--) protects the foam, it is possible to omit part or all of the cardboard box or decorative box used as the exterior material. In addition, the cup-shaped container and delicate multicolor offset printing give the product a luxurious feel, which has the advantage of motivating consumers to purchase it.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Synthetic paper production example Example 1゜(B), Mitsubishi Yuka ■ Polypropylene 1 Mitsubishi Noblen MA-6, l (trade name, melting point = 164°C) 87 parts Mitsubishi Yuka ■Weir High Density Polyethylene "Yucalon Hard EY-4
1 (trade name, melting point = 130°C, density 0.950 f/(
Q) After melt-kneading a composition consisting of 10 parts and 8 parts of heavy calcium carbonate using an extruder,
It was extruded into a sheet at a temperature of 0°C, and the sheet was cooled in a trench at a temperature of about 50°C.

Next, this sheet was heated to about 153° C. and then stretched four times in the longitudinal direction using the difference in circumferential speed between the roll groups to obtain a −axially stretched film.

Separately, a mixture consisting of 57 parts of polypropylene manufactured by Mitsubishi Noblen MA-31 (trade name, melting point -163°C) and 43 parts of heavy calcium carbonate was melt-kneaded using two extruders. 250 ml of molten material from the die on the stand
The film was extruded into a sheet at a temperature of 1.degree. C. and laminated on the front and back surfaces of the -axially stretched film to obtain a three-layer sheet.

After cooling this three-layer sheet to 60°C,
℃, stretched 8 times in the transverse direction using a tenter, passed through an open chamber set at 165℃ to heat set, cooled to about 60℃, and slit the edges. A synthetic paper was obtained in which the biaxially stretched base film of the intermediate layer had a thickness of 62 microns, and the uniaxially stretched films of the front and back layers each had a thickness of 30 microns.

On one side of this, add 100 parts of incyanate adhesive "AD-98OA" manufactured by Toyo Morton Co., Ltd. and A1)-980B.
, 12 parts'' was applied to a thickness of 15 μm, semi-dried, and (C) a corona discharge-treated film of styrene homopolymer with a density of 1.04 f,/c4 was dry laminated; Upon cooling, a composite film stamp with a total wall thickness of 137μ was obtained.

Examples 2 to 4 The composite was prepared in the same manner as in Example 1, except that the thickness of the polystyrene film was changed so as to obtain a composite stretched film and polystyrene film bonded product in which the thickness of the polystyrene back layer of (C) was as shown in Table 1. Bonded products [■] to [■] of stretched film and polystyrene film were obtained.

Example 5 "Diemilon PE" manufactured by Mitsubishi Yuka Co., Ltd. (polystyrene with a low density polyethylene content of 45 inches) was used as the material, (B) and (C) components used in Example 1, and these were extruded using three extruders. The mixture was melt-kneaded separately, fed to a Reiichi die, laminated in the die so that the sheet from the composition (lI3) became an intermediate layer, and then coextruded at 230°C. A three-layer sheet was obtained.

This three-layer sheet was once cooled to 60'C, then reheated to 135°C, stretched four times in the longitudinal direction using the difference in circumferential speed between the roll groups, and then reheated to 163°C, and then put into a tenter. The composite stretched film has a paper-like layer of (4) with a thickness of 20 microns, a base layer of ω) with a thickness of 62 microns, and a back layer of (C) with a thickness of 8 microns. I got [■].

Example 6 HI/PS (high impact polystyrene) unstretched film (manufactured by Mitsubishi Monsanto Kasei Co., Ltd.; styrene content: approximately 92 t, butadiene content: approximately 8 t). Original film (thickness: 350/l) was stretched at a stretching temperature of 120°C. Sequential biaxial stretching 1, 2 at a speed of 110 z/sec and a stretching ratio of 4 to 14 times, then treatment for 10 seconds in a mixed solvent of 15 parts of monochlorobenzene and 85 parts of normal hebutane at 20°C, and immediately in methanol. (for 30 seconds), dry, and have a wall thickness of 94 μ1, whiteness of 88 inches, and Peck smoothness of 2.
A 10-second polystyrene synthetic paper [■] was obtained.

Example 7 Instead of the synthetic paper in Example 1, clay coated paper manufactured by Company A with a wall thickness of 80 μm was used, and a polystyrene 21-film with a wall thickness of 20 μm was laminated thereon.

The decoration is made of film or paper (manufacturing side 1 to 5 on the cosmetic day). Slit the edge of the composite stretched film obtained in Production Examples 1 to 5 above, and cut the composite stretched film with a knife cutter at right angles to the film flow direction. 93.9m long and 63.6cm wide
The composite stretched film was then cut and stored in a sheet stocker.

After performing multicolor offset printing according to each purpose on the paper-like layer surface of the cut sheet-like synthetic paper, the printed portion was trimmed to obtain a film IV with illustrations.

Examples 6-7 Polystyrene synthetic paper [■] or clay coated paper [■]
] Multicolor offset printing is applied to the surface of the film [
■] or paper l] with illustrations.

Examples 1 to 4, Comparative Examples 1 to 3 For each decoration, cut out the four corners of the film or paper, make creases, and electrostatically fix it on the entire surface of the cavity of the female mold so that the printed surface is in contact with the mold. Next, after fitting the mold with a male mold having a large number of team holes (22), the mold cavity (
Length 200 crn 1 width 1.5 (ltM, depth 5 rtn
) was filled with foam particles (containing 6.8 weight + # of butane) whose surface was coated with hardened tallow oil (0.2 layers), and then 0.05 kg / c.
Rl G steam was introduced into the mold section for 1 minute to fuse the pre-expanded particles together, and then cooled for 3 minutes and the painted polystyrene foam molded article was removed from the mold.

Regarding this painted product, whether or not the printing is blurred or not,
For painting, the adhesive strength between film or paper and foam was investigated.

The results are shown in Table 1.

Example 5 A painted foam product was obtained in the same manner as in Example 1, except that expandable polystyrene particles containing low-density polyethylene produced by the following method were used as the expandable polystyrene particles.

Polymerization method In a pressure-resistant stirring vessel, a mixture having the composition shown below was stirred and heated at 90° C. for 4 hours to soften the polystyrene and impregnate the styrene monomer and n-pentane into the polyethylene.

Part by weight Styrene monomer 100 water
250 Sodium pyrophosphate 0.1 Polyvinylpyrrolidone
10 Diymil peroxide 0.
51-Pentane 10 Low-density polyethylene powder 40 (Mitsubishi Yuka ■ [Yukalon]
11i! (30J density = 0.920, MI 2.0 (average particle size 0.3 mm)) Then, it was heated at 120°C for 10 hours to polymerize the styrene monomer.

After cooling the obtained small spheres (particle size 0.85 to 1.3 mm),
It was separated from the aqueous phase, washed with water, and dried. The blowing agent is 6 in the particle.
．． It contained 5% by weight.

(Margin below) 25 26-

Claims (1)

[Scope of Claims] 1) A paper-like layer is a stretched film of a thermoplastic resin having a melting point of 145°C or more containing 8 to 65 weights of inorganic fine powder; Meat that makes up the surface I
I Composite film having a structure of at least 211 mm with a polystyrene film of 1 to 30 microns as the back layer. 2) The composite film according to claim 1, wherein the thermoplastic resin is polypropylene. 3) The composite film consists of a uniaxially stretched film and a paper-like layer.1.
Claim 2, characterized in that it has a 31 or more composite structure, and has a base layer made of a biaxially stretched polypropylene film between the paper-like layer and the back layer of the polystyrene film. + listed! Combined film. 1-14) The composite film according to claim 1, wherein the composite film has a wall thickness of 30 to 300 microns. 5) Contains 8 to 65% by weight of inorganic fine powder and has a melting point of 1
A stretched film of thermoplastic resin at 45°C or higher is used as a paper-like layer, and the surface opposite to this paper-like layer has a wall thickness of 1 to 30 mm.
A blank or decorative sheet of a label printed on the paper-like layer side of a composite film having at least two layers with a micron polystyrene film as the back layer is placed inside at least one of the molds consisting of a male mold and a female mold. The paper-like layer side of the decorative material is fixed in contact with the mold, and then pre-expanded polystyrene beads are filled into the cavity of the mold, and steam is introduced into the cavity to fuse these beads together. A method for producing a decorated polystyrene foam, comprising forming a foam and adhering the formed foam to a decorative sheet. −