JPH086002B2 - Polyvinyl chloride resin composition for food packaging - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a food packaging polyvinyl chloride resin composition, especially relates to a polyvinyl chloride resin composition suitable for molding of plastic wrap.

[0002]

2. Description of the Related Art Wrap films for foods containing polyvinyl chloride as a main component are used for 1) so-called stretch films for commercial use, which are used for food packaging in supermarkets and various food production areas, and 2) general households. Or it is roughly classified into household wrap film used in restaurants and the like. The required properties of the wrap film of 1) include ease of stretching of the film, transparency, surface glossiness, adhesion between the film and the packaging container or between the films, and packaging suitability for an automatic packaging machine. The wrap film of 2) is usually used by cutting a paper tube with a length of 10 to 500 m into a paper box, cutting it to a desired size with a saw blade provided on the edge, and using it. As a result, ease of cutting with a saw blade is required. Further, the adhesion of the film to the packaging container is required to prevent leakage of the contents and spillage, but if the films are easily sticky to each other, wrinkles are likely to occur and workability is impaired,
It is required to be harder and less sticky than the film of 1).

[0003] For these requirements, to use a high degree of polymerization of the polyvinyl chloride resin or reduce the amount of the plasticizer to be incorporated in the polyvinyl chloride resin composition is effective
It has been. However, these methods have a drawback that the moldability is remarkably deteriorated because the fluidity of the resin at the time of molding is lowered. Therefore, a method has been proposed in which a decrease in the plasticizer and the use of a relatively low degree of polymerization polyvinyl chloride resin having an average degree of polymerization of 600 to 1,000 prevent the decrease in fluidity due to the decrease in the amount of the plasticizer. However, the hitting the use of the wrap film after packaging food, it is often heated in a microwave oven, even that has been required the improvement of heat resistance of the film with adhesiveness to this for the container. Low
Since the polymerization product reduces the heat resistance of the film, it is desirable enhance the degree of polymerization of the polyvinyl chloride resin for this improvement <br/>, an average polymerization degree of balance between processability, especially 1,300 things around It is considered the best have come to so that. The low-polymerization product also affects the thermal stability of the film and has a problem of being easily decomposed during the molding process . As a countermeasure against this, a method of increasing the amount of the stabilizer was considered, but the cost was low. It is also up and not effective.

[0004]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to improve the fluidity and heat stability during extrusion processing, and to obtain the obtained film, which is required as a wrap film for foods in general households. cut by blade ease adhesion to the container, in which various characteristics such as heat resistance in a microwave oven or the like Ru is satisfied charging <br/> minutes, to provide a food packaging polyvinyl chloride resin composition .

[0005]

The polyvinyl chloride resin composition for food packaging according to the present invention has an average degree of polymerization of 1,250 to
100 parts by weight of 1,350 polyvinyl chloride resin, plasticizer 20-30
Parts by weight, Ca-Zn stabilizer 0.5-3.0 parts by weight, synthetic hydrotalcite 0.03-1.0 part by weight and pentaeryth
It comprises 0.1 to 1.0 part by weight of a mixed ester of litol, a higher fatty acid having 11 to 20 carbon atoms and a saturated dibasic acid having 4 to 6 carbon atoms.

Explaining the present invention in more detail, the polyvinyl chloride resin blended as a main component in the polyvinyl chloride resin composition for food packaging of the present invention has an average degree of polymerization of
It ranges from 1,250 to 1,350. This is in excess of 1,350, poor workability not to incorporate plasticisers large amount, resulting in a decrease in heat resistance and an increase in film plasticizer bleeding For that reason a large amount of blending the plasticizer. On the other hand, 1,2
If it is less than 50, it becomes difficult to cook at a desired temperature because the heat resistance of the formed film in a microwave oven is lowered, and the film becomes soft and the cut property is lowered.
Workability deteriorates, for example , the adhesiveness between the films increases.

As the polyvinyl chloride resin, in addition to vinyl chloride homopolymer, a copolymer of vinyl chloride and a vinyl-based monomer copolymerizable with vinyl chloride, each containing 50% by weight or more of vinyl chloride, vinyl chloride and various vinyl chloride resins can be used. graft polymer of polymer or polyvinyl chloride and a vinyl monomer, post chlorinated polyvinyl chloride polymers and mixtures thereof are encompassed, which are bulk polymerization, suspension polymerization, emulsion polymerization, any of solution polymerization, etc. Also included are those produced by the method of.

Vinyl-based monomers used for copolymerization or graft polymerization include olefins such as ethylene and propylene; halogenated olefins other than vinyl chloride such as vinylidene chloride and vinyl fluoride; vinyl acetate and vinyl laurate. Such as vinyl esters; 2-ethylhexyl vinyl ether, dodecyl vinyl ether, and other alkyl vinyl ethers; acrylic acid, methyl acrylate, ethyl acrylate, and other acrylic acids or their esters;
Methacrylic acid, methyl methacrylate, methacrylic acid 2-
Methacrylic acid or its esters such as ethylhexyl; maleic acid or its esters; acrylic derivatives such as maleic anhydride, acrylonitrile and styrene; N-substituted maleimides such as Nt-butylmaleimide and N-cyclohexylmaleimide. These are used alone or in combination of two or more. The polymer capable of vinyl graft chloride polymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, chlorinated polyethylene, polyurethane, polybutadiene <br/> down-styrene-methyl methacrylate copolymer, polybutylene <br/> Tajien acrylonitrile-(alpha-methyl) styrene
Examples thereof include copolymers , polybutyl acrylate, butyl rubber, polystyrene, styrene / butadiene copolymers and crosslinked acrylic rubber.

The plasticizer compounded as the second component in the polyvinyl chloride resin composition is a polyvinyl chloride resin.
It is used in a proportion of 20 to 30 parts by weight, preferably 25 to 30 parts by weight, based on 100 parts by weight. If the amount is less than 20 parts by weight , the resin is inferior in processability such as fluidity and heat stability, and continuous molding for a long time is difficult, and the adhesion of the molded film to a container becomes insufficient. And when it exceeds 30 parts by weight, fluidity, although the thermal processability of stability is well tends,
The formed film becomes soft and causes a decrease in cuttability, and also the heat resistance in a microwave oven expands, especially the film expands significantly when heated, and the heat resistance decreases.

Examples of the plasticizer include aliphatic dibasic acids such as di-i-butyl adipate, di-n-butyl adipate, di-i-nonyl adipate, dioctyl adipate, and di-n-butyl sebacate. esters; acetyl tributyl citrate, acetyl triethyl citrate, a hydroxy polycarboxylic acid esters such as acetyl citrate, tri-2-ethylhexyl; Asechiruri maytansinol acid, methyl palmitate, methyl stearate, stearic acid -
fatty acid esters such as n-butyl and butyl oleate;
Di-n-butyl phthalate, dihexyl phthalate, dioctyl phthalate, butylbenzyl phthalate, phthalic acid-n
- phthalic acid esters such as octyl -n- decyl pentaerythritol esters, glycol esters such as diethylene glycol benzoate; tricresyl shea Ruhosufeto, phosphoric acid esters such as triphenyl phosphate; epoxidized soybean oil, epoxidized linseed oil and the like Epoxidized oils; trialkyl trimellitate, tetra-n
-Octylpyromellitate, polypropylene adipate, other polyester-based plasticizers, etc. may be used alone or in combination of two or more. Depending on the fluidity of the composition in selecting or combining them. Judged that the melt viscosity at 200 ℃ was 1 × 10 ³ to 1 × 1
The porosity is preferably 0 ⁵ poise, preferably 1 × 10 ³ to 1 × 10 ⁴ poise.

The Ca-Zn stabilizer added as the third component to the polyvinyl chloride resin composition is 0.5 to 3.0 parts by weight, preferably 100 to 100 parts by weight of the polyvinyl chloride resin.
It is used in a proportion of 0.8 to 1.5 parts by weight, but if it is less than 0.5 parts by weight, the effect of improving the thermal stability is not sufficient and 3.0
If the amount is more than the amount by weight, bleeding of the stabilizer component, whitening of the film due to bloom, and excessive slidability of the stabilizer component may cause gelation delay during kneading, resulting in poor processability. Examples of Ca-Zn stabilizers include calcium salts of higher fatty acids such as 2-ethylhexyl acid, benzoic acid, isodecanoic acid, citric acid and sorbic acid, and zinc salts of higher fatty acids such as 2-ethylhexyl acid, isodecanoic acid and neodecanoic acid. And the like , and these are used alone or in combination of two or more.

The Ca-Zn-based stabilizer also serves as an antioxidant, and tris (nonylphenyl) phosphite , 2,2'-methylenebis (4-methyl-6-t) is used.
- Bed butylphenol), synthetic isoparaffin petroleum hydrocarbon, tridecyl alcohol, 1, 3-butanediol,
Dipropylene glycol, dehydroacetic acid and the like can also be appropriately used in combination. The amount of each of these is preferably 1 part by weight or less with respect to 100 parts by weight of the polyvinyl chloride resin.

The synthetic hydrotalcite compounded as the fourth component has the formula: Mg _1-x Al _x (OH) ₂ A ^n- _{x /} n.mH ₂ O (where 0 <x <0.5, 0 <m <1, a ^n- is one represented by an n-valent anion), is a ^n- especially in of these ^{_{CO 3 2-, HPO 4 2-,}} SO 4 2-, OH - or the like Those are preferable. The amount of synthetic hydrotalcite added is 0.03 to 1.0 part by weight, preferably 0.1 to 0.5 part by weight, based on 100 parts by weight of the polyvinyl chloride resin.
If it is less than 1 part by weight, the effect of improving the thermal stability is not sufficient and 1.0
If it exceeds the amount by weight, thermal stability is improved, but so-called gelation time is extended, and kneading during extrusion molding is incomplete, resulting in deterioration of processability. Further, the rise in the processing temperature due to this brings disadvantages such as an increase in the amount of energy and the occurrence of burns due to excessive heating.

The mixed ester of pentaerythritol , a higher fatty acid having 11 to 20 carbon atoms and a saturated dibasic acid having 4 to 6 carbon atoms as the fifth component is used as a so-called lubricant, and its blending amount is Is polyvinyl chloride resin 100
0.1 to 1.0 parts by weight, preferably 0.4 to 0.7 parts by weight
Parts by weight. If this is less than 0.1 part by weight, the effect as a lubricant is not sufficient, and if it exceeds 1.0 part by weight, the transparency of the film is reduced, and bleeding and blooming easily occur.
It delays gelation during kneading and reduces workability. The component ratio of the higher fatty acid and the saturated dibasic acid in the mixed ester is
1 to 4 mol of saturated dibasic acid to 6 to 12 mol of higher fatty acid,
In particular, saturated dibasic acid 1-2 with respect to 6-8 mol of higher fatty acid
Molarity is preferable because the lubricity is stable.

As the higher fatty acid having 11 to 20 carbon atoms,
Lauric acid, myristic acid, undecanoic acid, tridecanoic acid, pentadecanoic acid, palmitic acid, stearic acid, margaric acid, isostearic acid, 12-hydroxystearic acid, oleic acid, linoleic acid, ricinoleic acid, linoleic acid, n-heneicosanoic acid, Examples thereof include behenic acid, n-tricosanoic acid, and arachidonic acid, and these are used alone or in combination of two or more. Examples of the saturated dibasic acid having 4 to 6 carbon atoms include adipic acid, succinic acid, glutamic acid, etc.
Used in combination with more than one species. Among the mixed esters composed of the above components, the mixed ester composed of pentaerythritol, stearic acid and adipic acid and the mixed ester composed of pentaerythritol, oleic acid and adipic acid are particularly preferable from the viewpoint of lubricity.

When a higher fatty acid is used alone as the lubricant, the higher fatty acid reacts with the synthetic hydrotalcite when the resin is heated during the extrusion process, and for example, when stearic acid is used as the higher fatty acid. Magnesium stearate, and when isostearic acid is used , forms magnesium isostearate to reduce its function as a lubricant and a stabilizer, and also causes the extruded film to become cloudy and the resin to drift at the die mouth. significantly reduce the workability Te results in disadvantages such or to impossible molding.

The polyvinyl chloride resin composition of the present invention thus obtained further contains polyglycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene fatty acid alcohol ether and polyoxy as antifog agents and antistatic agents. Ethylene alkyl phenyl ether or the like can be appropriately used.

In addition, a well-known method such as an inflation method or a T-die method can be used for extrusion-molding a wrap film from the polyvinyl chloride resin composition of the present invention.

[0019]

The polyvinyl chloride resin composition of the present invention has a high degree of polymerization of the polyvinyl chloride resin contained as the main component and a relatively small amount of the plasticizer, but is in addition workability is excellent in fluidity and thermal stability is good, the obtained film is heat resistance required in a household wrap film, adhesion to the container, the properties such as workability (cutting, etc.) Satisfactory, uniform thickness and smooth surface condition can be obtained.

[0020]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to the description of these examples. Table 1 and the respective components were blended as shown in Table 2, mixed-with a Henschel mixer, were dry-up,
A wrap film having a thickness of 10 μm and a width of 300 mm was prepared from the cooled compound by a conventionally known inflation method. About the polyvinyl chloride resin composition used and the obtained wrap film, a roll test, by the following method ,
Measurement of melt viscosity, evaluation of cuttability with a saw blade, evaluation of adhesion to pottery, glass and stainless steel containers and heat resistance test were carried out, and these results are shown in Tables 1 and 2. In the table, Experiment Nos. 1 to 10 are the present invention, and 11 to 24 are Comparative Examples.

Roll test: The mixed formulation was tested on two rolls with a diameter of 3.5 inches.
Knead at 85 ℃, wrap the kneaded material on the roll, roll surface
Of plate-out on the surface or discoloration of kneaded material
The time until the deviation occurred was measured.・ Melt viscosity: JIS K-7210 using a flow tester (Shimadzu)
It was measured under the conditions of 200 ° C and a load of 50 kgf according to the reference test. -Evaluation of cutting performance with a saw blade: As shown in Fig. 1, a wrap film 2 wound around a paper tube 1
Was inserted into a rectangular container 3, a saw blade 4 was attached downward to the lower end of the side wall of the container 3, and the container 3 was fixed in a state inclined by 10 ° with respect to the horizontal plane. Raise vertically over the saw blade 4 rewinding the lap film 2 in the direction of the arrow, Ri taken its tip Tensilon UTM-III-500 (tensile tester, Toyo Baldwin Co., Ltd., trade name, not shown) to I attached it. The load when the tip of the wrap film was pulled at a pulling speed of 500 mm / min and the wrap film was cut was measured, and the following evaluation was performed based on the value. ◎ Less than 500gf ○ ・ ・ ・ 500 to 2,000gf × 2,000gf or more

Evaluation of adhesion to container: Pottery, glass, and stainless steel containers were filled with water, and the whole container was covered with a wrap film, then the container was tilted and the state of water leaking or spilling was observed. Then, the following criteria were evaluated. ◎ ・ ・ ・ No leak spill ○ ‥ Slight leak spill but no problem in practical use × ・ ・ ・ A lot of leak spills cannot be put to practical use ・ Heat resistance test: For each wrap film, a method for measuring heat resistant temperature of wrap film for food packaging in Tokyo It measured based on.

The details of each component used in the examples are as follows.
It is as follows. -Polyvinyl chloride resin (manufactured by Shin-Etsu Chemical Co., Ltd.)-Plasticizer: di-i-nonyl adipate di-n-alkyl adipate epoxidized linseed oil-Ca-Zn composite stabilizer SC-26 (Asahi Denka Kogyo KK)・ Hydrotalcite: Mg_0.67Al_0.33(OH)₂・ (CO₃)_0.17・ 0.3H₂O (Kyowa Chemical Industry Co., Ltd.)-Mixed ester:A ... Mixed ester of pentaerythritol, adipic acid and oleic acid (1: 1: 6) (manufactured by Henkel Hakusui)B: (1: 1: 6) mixed ester of sorbitan, adipic acid and oleic acid C ... (1: 1: 6) mixture of diethylene glycol, adipic acid and oleic acid  Steal ・ Other additives: Polyglycerin fatty acid ester (anti-fog agent, Riken Vitamin Co., Ltd.)

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

The present inventionPolyvinyl chloride resin for food packaging
CompositionAccording to  Excellent fluidity and heat stability during extrusion moldingThe
R;  The resulting film is saw bladeRiEasy to cutYes; Of the obtained film Adhesion to containerIs excellent
R; Has sufficient heat resistance against heating in a microwave oven, etc .; And so on.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing an outline of a cutting property evaluation test method with a saw blade in Examples.

[Explanation of symbols]

 1 ... Paper tube, 2 ... Wrap film, 3 ... Container, 4 ... Saw blade.

Claims (1)

[Claims] 1. A polyvinyl chloride resin having an average degree of polymerization of 1,250 to 1,350, 100 parts by weight, a plasticizer, 20 to 30 parts by weight, and Ca-Zn.
0.5 to 3.0 parts by weight of system stabilizer, synthetic hydrotalcite 0.
Polyvinyl chloride resin composition for food packaging comprising 03-1.0 parts by weight and 0.1-1.0 part by weight of mixed ester of pentaerythritol , higher fatty acid having 11-20 carbon atoms and saturated dibasic acid having 4-6 carbon atoms Stuff.