JPS5820445A - Biaxial stretching styrene group resin sheet for molding - 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 biaxially oriented styrene-based (9) resin film for molding.
Regarding organic solvent resistance, 1
This invention relates to a biaxially oriented styrene futures/1-fat sheet for container molding which has improved oil resistance and the like.

Biaxially stretched styrene resin sheet 1 does not contain any substances harmful to the human body, has excellent waist strength,
In addition, because of its excellent moldability, it is often used as a lightweight container for storing food.

One of the packaging formats of this kind of high-quality containers for storing foods that are currently widely sold on the market is the overlapping method, in which the container containing the entire food is overlapped with a stretch film. In Method 1, food is stored in containers such as dish-shaped or lunch box-shaped containers, and then a so-called stretch container made of soft polyvinyl chloride, polyethylene, ethylene-vinyl acetate copolymer, polybutadiene, etc. Cover (overlap) the entire opening of the container with film, and cover the flange of the container so that there are no wrinkles on the upper f-law covered surface of the film. With the inflection point as the inflection point, the stretch film is pulled onto the lower wall of the container, and the stretch film is fixed at the bottom of the container by taking advantage of its self-viscosity or by using a heat roller, etc., and the coating process is completed, resulting in the form of an m+ product. In this packaging method, if the slip between the stretch film and the flange of the container is poor, the stretch film
] There is a problem in that wrinkles remain on the coated surface, reducing the commercial value of products packaged using the overlap method.

A biaxially stretched sheet of styrene resin is used as raw material 1, and is formed into a desired shape by vacuum forming method or king air forming method.
Although this overlap method has been adopted as a coating method for containers, this type of container has the disadvantage of poor slipperiness with the trench film.

Containers made of biaxially oriented styrene resin sheets also have the disadvantage that the liquid components, -', which are commonly contained in the foods stored therein, are easily attacked by organic chemicals, making them easy to break. In addition, when a flexible polyvinyl chloride film is used as a stretch film to cover a container containing food, plasticizers and other additives may be added to the film at the flange of the container. It had the disadvantage that it was eroded by chemicals and deteriorated, making it easy to break.

In order to improve the organic solvent properties, oil resistance, etc. of biaxially oriented styrene resins, thin films of polyethylene, polypropylene, polyamides, etc., are processed by extrusion lamination, coextrusion, so-called dry lamination, or heating. Techniques have been proposed in which layers are laminated using a close contact method or the like. but,
Even though the sheet laminated with side 1 oil-based film like the one above has improved oil resistance, it still suffers from stretching as described above, and poor slipperiness with the film. There were drawbacks.

Under such circumstances, the present inventor has sought to provide a biaxially oriented styrenic resin sheet for container molding that has good slip properties with stretch films and has improved organic solvent resistance, oil resistance, etc. As a result of extensive research aimed at this purpose, we have completed the present invention.

However, the gist of the present invention is that at least one side of the biaxially oriented styrenic resin sheet has an average particle diameter of 7 to 7.
A film with improved oil resistance characterized by forming a film with a thickness of 7 to 30μ containing an acrylic acid ester resin and an epoxy resin blended with a fine powder of /Sμ. It consists of biaxially oriented styrene resin sheets for molding.

The present invention will be explained in detail below.

In the present invention, styrenic resins include general purpose polystyrene, copolymers of styrene and other copolymerizable monomers containing styrene at or above the SO weight coefficient, rubber-reinforced polystyrene containing a small amount of rubber component, etc. = 4- All said. Monomers that can be used to copolymerize with styrene include α-methylstyrene, acrylic acid and esters thereof, methacrylic acid and various esters, maleic anhydride, and the like. As a rubber component,
Examples include polybutadiene, random copolymers and block copolymers of butadiene and other copolymerizable monomers containing 0% by weight or more of butadiene. Monomers that can be used to copolymerize with butadiene include styrene, α-
Methylstyrene, acrylic acid and esters of et al.
Examples include esters of methacrylic acid and methacrylic acid, acrylonitrile, methacrylonitrile, etc. In addition to rubber components, examples include polyisoprene, polychloroprene, terpolymer of ethylene-propylene-diene monomer, and the like. The methods of incorporating the rubber component of Kobara into styrene resin include: (1) dissolving a predetermined amount of the rubber component in a styrene monomer or a monomer mixture containing styrene and polymerizing the monomer; (2) polystyrene Or styrene and other glue 1
A method of melt-mixing a rubber component into a copolymer with
One method is to prepare a polymer with a high degree of rubber component in advance by the method described above, and then dilute it by adding a polymer containing no rubber component to the mixture to obtain the desired rubber component content. .

The sheet according to the present invention is obtained by biaxially stretching the styrene resin resin when forming it into a sheet, or by biaxially drawing the styrenic resin 4-sheet into a 11'AK sheet.
It is possible to use the generally known stretching method using either one tenter method, inflation method, or John method.

A biaxial 1-stretch styrene-based resin sheet according to the present invention 1"J" has at least one side containing an acrylic v1-ester resin and an epoxy-based potato/fat coating of ~30μ)
1q is formed.

In the present invention, the acrylic ester resin refers to a homopolymer of a single hanging compound of acrylic esters or methacrylic esters, or a copolymer of two or more of these monomer compounds, or t et al. unitary quantity ``body combination!l/
! Examples include copolymers containing /J as a main component and other copolymerizable monomer compounds.

Examples of acrylic esters include methyl acrylate,
Ethyl acrylate, n-propyl acrylate-1, i
-propyl acrylate, n-butyl acrylate, j
-Butyl acrylate-1-, cyclohexyl acrylate, -ethylhexyl acrylate-1-, decyl acrylate, lauryl acrylate, and tridecyl acrylate acid with 01 to C22 alkyl esters. Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, 1-propyl methacrylate-1, n-butyl methacrylate, 1-butyl methacrylate-I, cyclohexyl methacrylate-1, C1-C2□ alkyl esters of methacrylic acid such as suethylhexyl methacrylate, decyl methacrylate, lauryl methacrylate, tridecyl methacrylate, and stearyl methacrylate are mentioned. Other mono-clear compounds that can be copolymerized with compounds include acrylic Q
(Q, α, β-unsaturated monofatty acids such as methacrylic acid, itaconic acid, crotonic acid, maleic acid, etc., hydroxymethyl ester, hydroxyethyl ester, hydroxypropyl ester of acrylic acid/l/, ゛.

° − -Hydroxyalkyl esters such as hydroxybutyl ester, hydroxypentyl ester and hydroxyethyl ester, hydroxymethyl ester of methacrylic acid, hydroxyethyl ester, hydroxypropyl ester, hydroxypenyl ester and hydroxyhexyl ester, glycidyl acrylate, tetrahydro Acrylic acid epoxidized alkyl esters such as furfuryl acrylate, acrylamide,
Examples include N-methylolacrylamide, styrene, vinyl acetate, acrylonitrile, and the like.

The above-mentioned acrylic ester resin may be used alone or in combination of two or more. In addition, if the glass transition point of the acrylic ester resin IIWu is 30°C or higher, the blocking resistance of the product sheet (the property of not adhering to each other when multiple sheets of the same type are stacked) will be excellent. This is preferable.

In order to apply the above-mentioned acrylic ester resin to the base sheet, it is preferably in the form of an emulsion, and it is preferably manufactured by emulsion polymerization.

In the present invention, the epoxy resin is defined as having an epoxy equivalent of /
Refers to an epoxy-position 1 fat having a molecular weight of Sθ~1000 and a molecular weight of 300~/θ0θ. Specifically, in addition to glycidyl ether type epoxy resins derived from polynuclear polyhydric phenol compounds such as bisphenol A type epoxy resins and noholac type epoxy resins, glycidyl ethers derived from mononuclear polyhydric phenol compounds. mold epoxy resin,
Glycidyl ether/glycidyl ester type epoxy resin derived from aromatic oxyacids, glycidyl ester type epoxy IQI derived from aromatic/fatty polycarboxylic acids or anhydrides thereof, etc. Let￥, N-glycidyl-type Ebogishii derived from aromatic 71j amine compounds
, halo j1 force η; each single layer of glycidyl ether spread from the polyol 1] Ebogishi 0, 411-・Flysuke Kaage et al.

When applying the above epoxy resin to the base sheet, ir:l
"One or more epoxy resins."
Mix the two, add emulsifier 4 to the combined mixture, and add epoxy 11, fat emulsion, hardening agent, ethanolamine, dicyandiamide, dicylylenediamine, diethylene), liamine, Fatty amines such as 1/l-riethylenetetramine, diethylamine, propylamine, and diethylenepentamine can be added.

No. 11 bow 1 according to the present invention, a mixed emulsion of the acrylic acid ester resin emulsion and the epoxy resin emulsion is applied to at least one side of the divalent monostretched styrene resin sheet, and water is evaporated. It has a coating formed on it. Among the resins constituting the coating, acrylic acid Nisder-based 4υ resin provides flexibility and strength to the skin 114, and at the same time has linearity that increases the adhesive strength with the base resin and resin, and epoxy-based resin ( Also, [fat is a film] It functions to improve oiliness and organic solvent resistance.The mixing ratio of both sides is determined by the adhesion of the film to the base styrene resin and the flexibility of the film. , oil resistance of the film, jl of the product film
iiiI decided to take into consideration blocking properties, acrylic ester resin and epoxy, ii'! 1 heavy fat (
1 ratio, it can be changed in the range of 97=3 to gO:20.

The coating formed on at least one side of the base sheet includes '
J<7 diameter is /~/,! A small amount of fine powder of i'μ is blended. This fine powder forms irregularities on the surface of the coating formed on the base sheet, causing slippage of the stretch film.
'f direction]

Types of fine powder include inorganic substances such as calcium carbonate, magnesium carbonate, magnesium silicate, titanium oxide, aluminum oxide, aluminum hydroxide, -]1- barium sulfate, talc, kaolin, diatomaceous earth, and polyamides. Acrylic 1st grade ester type [
Halo, epoxy-based 4ijimeji, polyesters, urine'
! A rich substance such as ξ is opened. These fine powders preferably have a particle diameter in the range of 7 to 3-μ, especially those in the range of 7 to 3-μ.

-I- The fine powder may be blended into a mixed emulsion and applied to the base sheet. The ratio to be added to the mixed emulsion can be selected within the range of 05 to /θ weight parts to 700 weight parts of the resin component of the emulsion.

In order to form a coating on at least one side of the base sheet, a resin mixed emulsion containing the above-mentioned fine powder is applied and water is evaporated. As the coating method, known methods such as gravure coating, offset coating, reverse roll coating, air knife coating, kiss roll coating, etc. can be employed. After coating, dry with hot air or an infrared heater. If the thickness of the film formed in this way is too small, the oil resistance of the product sheet 1 (No, organic solvent resistance may be improved)
On the other hand, if it is too large, the drying process will take a long time and the formed film will be prone to cracking. The thickness of the cover ranges from / to 30 μm, especially from 3 to 30 μm. The range of 2θμ is preferable.

The biaxially oriented styrenic resin sheet according to the present invention has a coating containing the acrylic ester resin and epoxy resin formed on at least one side of a biaxially oriented styrenic resin sheet as a base. be. This coating does not affect the stiffness or moldability of the biaxially oriented styrene resin sheet as the base, and does not impair the transparency even if the base sheet is transparent. Ni-tai 1 according to the present invention
Stretched styrene type; 1M resin sheet can be used to manufacture food storage containers such as dish-shaped containers and lunch box-shaped containers by vacuum forming, king air forming, and other forming techniques. .

If the coating is formed on only one side, should the coating be in contact with the stored items on the inside of the container?

The present invention (/(2I stretched styrene system #l
If the following effect is given, its industrial profit value Ill'1 is as large as IJg.

(1) 211Iliil rolled-leaf steel l/in system according to the present invention, with a stretch film (:fley I1.), the distance between the containers is 11°, and the part between the containers is 4. It may leave wrinkles on 1r11, so please remove it.

(2) The 21lllllllllllllllllllllllllllllllllllllllllllllllllllloyed styrene-based τ3 "Si1-beating) sheet" according to the present invention: The manufactured product is made of a stretch film, a plasticizer mixed with vinegar, and a plasticizer that is contained in the food to be stored. I-fu is attacked by chemicals n rj!・There is no problem of the container being damaged.

Hereinafter, the present invention will be explained in detail based on examples.
The present invention (hereinafter referred to as "the gist of the present invention") is not limited to the following examples.

Examples/Comparative Examples/Acrylic ester WFI Jlt' containing methyl methacrylate as a main component and methyl acrylate, ethyl acrylate, butyl acrylate, etc. as subcomponents.
f emulsion (manufactured by Nippon Tsumugi Co., Ltd., product name: “Jurimar”)
) and acrylic acid varnish t':lI? containing ethyl acrylate as the main component and methyl acrylate, butyl acrylate, etc. as subcomponents. f emulsion and an epoxy resin emulsion (Yuka Shell Co., Ltd., product name "Epicote G,
4-1+j parts, 25 parts by weight, and 6 parts by weight were mixed.

This mixed emulsion further contains 2. as a curing agent. B
of ethanolamine was added and mixed.

To the above mixed emulsion, 1.23 parts by weight (M) of talc (average particle diameter 3 gμ) was added and mixed based on 15 parts by weight of 700 solids.

Spread the above mixture to a thickness of 0.2! One side of the biaxially oriented polystyrene sheet of irmn was coated using the Giscoat method.
1. Water was dried using an infrared lamp. The thickness of the sealed material after drying was μ on the left.

(a) Testing the oil resistance of the sheet (with the above-mentioned coating).
1441ii''l'ft41), C' (1 product name ``Dia Lap'') was layered, this sheet was rolled into a cylindrical shape with a diameter of θ rust, and stress was applied to the sheet.
It was left in Muro Lake at - ℃. After a certain period of time, JISK
Test 1 test pieces based on -6g72 were punched out in the drawing direction, and the tensile strength of the sheet was measured based on JIS K-tg7 (Test I') (number of 6 pieces). The results are shown in Table 7.

In addition, the sheet without coating is also treated in the same way,
The results of the same evaluation are summarized as the 7th sheet of Comparative Example/.
It is shown in the table.

16- (b) Sliding property test between the flanged part of the dish M container and the stretch film Furthermore, a sheet was heated by the hot plate contact heating method as the sortra raw material of the above example, and the length/SO simple and the width 10
A flanged dish-shaped container (commonly referred to as a meat tray) having a storage section with dimensions of 0 meat and 20 dragons in depth was manufactured by the Taku molding method. The raw and coated surface was placed on the side of the article storage section of the dish-shaped container. With the opening of the resulting container facing down, the container flange contacts and rubs against a polyvinyl chloride stretch film ("dia wrap") fixed by the frame edge, and the contact surface between the container flange and the stretch film The degree of slippage was evaluated.

Incidentally, sheets without a coating were also evaluated in the same way. The evaluation results were as follows.

Sheet container of Example: The slipperiness between the container flange and the stretch film was good, and no wrinkles were formed on the stretch film.

Sheet container of Comparative Example 1/--The container flange and the stretch film were in close contact with each other and did not slip at all.

(/'1 Contact test between the flange of a dish-shaped container and a stretch film I) Flange of a dish-shaped container obtained during the test in section (b) above) η15 k, polyvinyl chloride stretch film (
``Dialatsun°'') was used for 7 peels, and the end of the stretch film was fixed to the bottom wall of the container by taking advantage of the self-attaching property of the stretch film. Store the container in this way at 23°C.
Cracks that occur on the flange of the container due to exposure to room temperature 7'
I was able to see the situation with the naked eye. The results are shown below.
Shown in the table.

A similar evaluation was carried out for containers manufactured using sheets (comparative example/) without a subject as raw material, and the results were used in the second
Shown in the table.

The same test as above in Table 2 was carried out at a temperature of around 5°C, which is the temperature at which these dish-shaped containers are used for actual investigation. I observed it. The results are shown in Table 3.

= 19- From the above (a), (b), and (・Test 51!・(), the following becomes clear.

(1) Biaxially oriented styrenic resin sheet according to the present invention;
It has excellent slipperiness with the stretch film and does not leave wrinkles on the coated surface of the opening of the container, resulting in a product with an excellent appearance.

(2) The biaxially oriented styrenic resin sheet according to the present invention exhibits extremely little decrease in strength even when it comes into contact with a stretch film, and there is no deterioration of the container flange at all. Not easily affected by plasticizers.

Claims (3)

[Claims] (1) On at least one side of a biaxially oriented styrene resin sheet, fine powder with a diameter of /~/!iμ is blended with an acrylic ester type 491 resin and an epoxy resin. A 2+IQL oriented styrenic resin sheet 1- for embossed molding with improved oil resistance of 11 units, characterized by the formation of a film containing J5a-S/~, ?θμ. (2) The resin that forms the film is an acrylic ester! The weight ratio of fat and epoxy resin is 7:3 to 3g.
The biaxially stretched styrenic resin sheet for molding according to claim (1), which is a mixture in which θ is in the range of 20. (3) The fine powder formulation 1 is the resin component 1 that forms the coating.
Biaxially oriented styrene system 4171 for molding according to claims n) to (2), characterized in that it is 0.5' to 0.00 parts by weight. Monthly sheet.