JPS58168616A - Wrapping film - Google Patents

Abstract

PURPOSE:A wrapping film which does not contaminate food, comprising a flexible thermoplastic resin prepared by polymerizing a vinyl chloride monomer or its mixture with another specified monomer in an aqueous medium in the presence of a specified thermoplastic polyurethane elastomer. CONSTITUTION:100pts.wt. vinyl chloride monomer or mixture containing a vinyl chloride monomer and a monomer copolymerizable therewith and capable of providing a homopolymer having a glass transition point below 30 deg.C is polymerized with 10-200pts.wt. thermopolastic polyurethane soluble in a vinyl chloride monomer and having a softening point of 20-100 deg.C, in the presence of an aqueous medium, a suspending agent and an oil-soluble initiator. The produced flexible thermoplastic resin is formed into film to obtain a wrapping film. The above flexible thermoplastic resin shows flexibility even in an unplasticized state and is excellent in transparency, low-temperature resistance, chemical resistance and heat resistance. Wrapping films prepared from the resin by film molding are suitable for use in food packaging.

Description

[Detailed description of the invention] The present invention relates to wrap films.

In the present invention, the wrap film refers to household food wrapping films, food delivery sIK containers (covering films, stretch wrappers, etc.).

Conventionally, soft vinyl chloride polymers or vinyl chloride-vinyl chloride lyso/copolymers have been used as materials for wrap films. However, wrap films produced from these vinyl chloride polymers have the following problems.

0) Since the film contains a large amount of softening agent, a large amount of the softening agent precipitates on the surface of the film during use, contaminating the food. Contamination is particularly noticeable when packaging oily foods.

(The adhesive agent containing a large amount of 11j?J precipitates on the surface of the film, impairing the slip properties of the film.

Book 118@Kan et al. have diligently investigated these problems and completed the present invention. That is, the present invention is capable of submersible in vinyl chloride monomer.
9. Vinyl chloride monomer or vinyl chloride in the coexistence of a thermoplastic polyurethane elastomer with a softening point of 20 to 100° C. and a thermoplastic polyurethane elastomer of 100 parts by weight to 910 to 200 parts by weight of the monomers described below. Molding a soft thermoplastic resin into a thin film by polymerizing in an aqueous medium a monomer and a monomer mixture with a monomer that can be copolymerized with the monomer and provides a homopolymer with a glass transition temperature lower than 60°C. It is a wrap film made of

The novel soft thermoplastic resin used in the present invention includes
A monomer mixture of vinyl chloride monomer (hereinafter referred to as MVC) or hMVc and a monomer copolymerizable with it and whose homopolymer has a glass transition temperature lower than 30°C (hereinafter referred to as MYC monomer) MY
10 to 200 parts by weight of a thermoplastic polyurethanoelastomer that is CK soluble and has a softening point of 20 to 100°C (hereinafter abbreviated as MvC soluble 11TPU), an aqueous medium, a suspending agent, and an oil #1 initiator. It is produced by polymerization in the presence of.

It is produced by polymerizing MVC monomers under the same conditions, but the nature of this reaction is confirmed.
, hi V CIII#! IIT P UkUM
It is also presumed that O is caused by chemical bonding in the acid bath (that is, a reaction called rigid graft copolymerization) with the VC monomer. That is, it can be inferred from the fact that, compared to a polymer blend of TPU and PVC at the time of compounding, the polymer produced according to the present invention undergoes significant modification, that is, it is superior in terms of processability, flexibility, etc.

The MVC-soluble TPU in the present invention is one that essentially dissolves into WCMVC monomer VCf under the polymerization conditions for producing the flexible thermoplastic resin in the present invention, and has a softening point of 100'-20°C, Preferably $160'~30℃
It belongs to The material with a softening point exceeding 100°C is MVC monomer VCIl! If the temperature is lower than 20°C, the resulting polymer will have poor tensile strength and heat resistance.

In addition, a non-yellowing type using an aliphatic diisocyanate as the raw material for M V CiiJ is preferable.
1 non-yellowing type has good UV stability, whereas non-yellowing types other than %(1) tend to cause the produced polymer to be colored after polymerization. MVC effective for the present invention
A suitable example of PU is Vandex T-52 manufactured by Dainippon Ink & Chemicals.
65, Bandex T-525, etc.

Invention K>Vsl, MVC possible @IITPUH1 preparation i1
Polymerization is initiated by coexisting 10 to 200 parts by weight, preferably 20 to 150 parts by weight, of MV ('4u MVC monomers per 100 to 111 parts by weight).

MY (41-!, based on 100 parts by weight of MVC monomer, if the amount is less than 101 parts by weight of MVC-based monomer, satisfactory softness cannot be obtained in the resulting polymer, whereas if it exceeds 200 parts by weight) , the degree of polymerization becomes slow, which is not preferable.

In the present invention, the MVCIJ TPU content in the produced polymer is preferably 0 to 80 weight-1, more preferably 17 to 65 weight-1. If the weight is less than 10%, it is difficult to obtain satisfactory softness;
This is because if it exceeds 100%, the heat resistance will tend to deteriorate and the %% will increase, which is economically undesirable.

In the present invention, monomers that can be copolymerized with MVC and whose homopolymer has a glass transition temperature lower than 30°C include olefins such as ethylene and propylene, vinylidene chlorides and other vinylidenes, Vinyl esters such as vinyl acetate, n-7' methyl vinyl ether natonovinyl ethers, butyl acrylate, acrylic@
Examples include acrylic esters such as -2-ethylhexyl and methacrylic esters such as -2-ethylhexyl.

In addition, the amount used is preferably 50% in the MVC monomer.
weight - or less, more preferably 50% by weight or less.

This is because if the weight exceeds 50, the processability, heat resistance, etc. of the resulting polymer deteriorate.

The polymerization method employed in the present invention may be either a suspension polymerization method or an emulsion 1 method, but the suspension IIs used in the suspension polymerization method may be a known suspending agent. For example, partially saponified polyvinyl Alcohol, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, polyacrylic acid, vinyl ether-maleino acid anhydride copolymer, zolatin, etc. are used, and these may be used alone or in combination.

The amount of these used is about 1 to 2 parts by weight based on the aqueous medium.

The oil bath polymerization initiator used in the present invention may be any known polymerization initiator. For example, azo compounds such as azobisisobutylvaleronitrile, lauryl peroxide, di-
Examples include organic peroxides such as 2-ethylhexyl peroxydicarbonate and t-butylno(-oxyvivalate).

The amount used is Q, 01 for the MVC monomer at the time of preparing the frame.
〇11'14Ktk which is about 2 weight ginseng)! :,,7 [body/(MVC possible#
The preparation ratio of IITPU + MVC monomer) is 1/1 to 3/
1 is good. This is because polymerization is unstable if the cough ratio is less than 171 (9), and it is not economically advantageous for the wrinkle ratio to exceed 3/1.

The polymerization temperature is preferably 30 to 70°C, preferably 40' to 60°C. This is because the polymerization rate tends to slow down below 30°C, which is not industrially advantageous.

Moreover, if the temperature exceeds 70°C, the heat resistance of the resulting polymer tends to deteriorate, which is not preferable.

In the present invention, known chain transfer agents such as tricreno, mercaptoethanol, etc. may be used.

Additives used in the field of PvC processing, such as stabilizers, can be added to the soft thermoplastic resin in the present invention.

As the method for molding the soft thermoplastic resin into a thin film in the present invention, processing methods used in the field of PVC processing, such as the T-die method, inflation method, calender roll method, etc., can be employed.

The new soft thermoplastic resin used in the present invention is
It is flexible even without plasticizer, and has excellent transparency, fire resistance, chemical resistance, and heat resistance. It is.

A wrap film formed by molding this resin into a thin film does not contaminate foods and has appropriate adhesiveness, so it has good packaging workability.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. All parts in the examples are parts by weight.

Film hardness, tear strength, and embrittlement temperature are JI8 650
The tensile strength and elongation were measured at HJI8 and 6725, and the light transmittance was measured at JI8 and 6714.

The film dissolution test was measured as follows. That is, the film was immersed in 2011 ethanol or lard oil at different temperatures for different times, the eluate was extracted with chloroform, and the extract was directly injected into a gas chromatography system to quantify the content.

Example 1 Stainless steel autoclay lK, MVC with internal volume 10j
30 parts of TPU (Punchx T-5265 manufactured by Dainippon Ink and Chemicals), 200 parts of pure water, partially saponified polyvinyl alcohol (Go-Sevenol KH- manufactured by Nippon Gosei ■)
17) 105 parts of medium sil peroxydicarbonate was charged into 18 parts of di-2-ethyl, and after replacing the inside air with N, 70 parts of MVC was charged. After reacting at 58° C. for 15 hours, unreacted monomers were removed and this was dehydrated and dried to obtain 90 parts of a powdery polymer.

1 part of forged calcium stearate and 5 parts of zinc stearate were added to 100 parts of the obtained polymer, and PVC
Using an extruder, the temperature is 170°C and the thickness is 2 using the T-die method.
A 0s film was molded. The physical properties of this film are
The dissolution test results are shown in Table 1112.

When this film was used for manual packaging, it did not become excessively sticky and "Bitsura 9" was written on various customer containers.

Comparative Example 1 Too parts of polyvinyl chloride (P=1050), 50 parts of dioctyl phthalate, 1 part of calcium stearate
Zinc stearate α5 When this film was used for hand wrapping, it was so sticky that hand wrapping could not be done smoothly.

Comparative Example 2 For 100 parts of polyvinyl chloride (P=1050), 40 parts of diotatylazide, 1 part of calcium stearate
1 part, zinc stearate (L5 parts) was blended, and a film was formed in the same manner as in Example 1.

The results of the elution test for this film are shown in Table 2.

ND: Q, less than 05 pfl'r1 Unit: ppm The eluate was found to be dioctyl adipate by gas chromatography analysis.
1 Patent applicant: Toagosei Chemical Industry Co., Ltd. Kinsha

Claims (1)

[Claims] t Submersible in vinyl chloride monomer and has a softening point of 20 to 1
100 parts by weight of the monomer or monomer mixture described below at 00°C
In the coexistence of 10 to 200 parts by weight of a thermoplastic polyurethanoelastomer, a vinyl chloride monomer or vinyl chloride monomer and a homopolymer copolymerizable therewith and having a glass transition temperature lower than 30°C are added. A wrap film made by forming a soft thermoplastic resin into a thin film by polymerizing a monomer mixture with the given monomer in an aqueous medium.