JPS5930850A - Heat-shrinkable film and sheet - Google Patents

Abstract

PURPOSE:To prepare a film or sheet shrinkable at low temperature and having remarkably improved weatherability without lowering the transparency, by compounding a hindered amine compound to a specific vinyl aromatic hydrocarbon- conjugated diene block copolymer composition, and drawing the film or sheet prepared therefrom. CONSTITUTION:100pts.wt. of a block copolymer composed of at least two polymer blocks (A) composed mainly of vinyl aromatic hydrocarbon and at least one polymer block (B) composed mainly of conjugated diene, wherein the molecular weight of the block (A) is 10,000-50,000 or is >50,000 and the weight ratio of the block group having the molecular weight of 5,000-35,000 to the group having the molecular weight of >=50,000 is >=1/6, and the weight ratio of the vinyl aromatic hydrocarbon to the conjugated diene is 60:40-90:10, is compounded with 0.005-5pts.wt. of the compound having the group of formula (R1- R4 are alkyl), e.g. 4-acetoxy-2,2,6,6-tetramethylpiperidine. The composition is drawn uniaxially or biaxially to obtain a film or sheet having a thermal shrinkage of >=10% to the direction of orientation at 90 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to heat-shrinkable films and sheets that are transparent, have excellent low-temperature shrinkability, and excellent weather resistance.

Shrink wrapping using heat-shrinkable film has recently become the number one food product because it can neatly eliminate the double wrinkles that were unavoidable with previous packaging technology, and it also allows for quick packaging of products and irregularly shaped items. Its use for packaging is increasing. In particular, stretched films of vinyl chloride resin are widely used as heat-shrinkable fillers because of their good shrinkage properties, transparency, gloss, printability, suitability for packaging machines, etc. However, there is a strong demand for a substitute for vinyl chloride resin due to hygienic problems associated with vinyl chloride monomers and plasticizers, and the problem of hydrogen chloride generation during incineration.

On the other hand, block copolymer resins made of vinyl aromatic hydrocarbons and conjugated dienes do not have the above problems and have good transparency and impact resistance, so they are widely used as materials for food packaging containers. It is being done. However, conventionally known block copolymers are unsuitable as heat-shrinkable packaging materials that require low-temperature shrinkability because the stretching temperature is high and the temperature at which shrinkage occurs is also high.

For example, JP-A No. 49-102494 and JP-A No. 49-Sho.
Publication No. 108177 describes a packaging film obtained by biaxially stretching a block copolymer having a styrene hydrocarbon content of 50 to 95% by weight, and a composition in which the block copolymer is blended with a styrene resin. However, such a film cannot achieve a sufficient shrinkage rate unless the heat shrinkage temperature is about 100°C or higher. Methods for improving the low-temperature shrinkability of block copolymers have been attempted in JP-A-50-6673, %, and JP-A-5-5544. However, these methods have problems such as having to set very limited temperature conditions depending on the raw material resin to form the film, and having to prepare a composition with good cross-wire pattern in advance, so it is not easy to implement. It had the disadvantage of being a young child.

In view of the current situation, the present inventors have carried out extensive studies on block copolymer films and sheets with excellent low-temperature shrinkability, and have found that the vinyl aromatic hydrocarbon polymer blocks that make up the block copolymer are A block copolymer having a molecular weight in the range of or a block copolymer containing a vinyl aromatic hydrocarbon polymer block with a relatively small molecular weight and a vinyl aromatic hydrocarbon polymer block with a relatively large molecular weight in a certain ratio. Can be stretched at relatively low temperatures,
It was discovered that the purpose could be achieved, and the patent application
No. 2989, Patent Application No. 1987-99384, Tokuse Sho 57-
No. 99885 was filed. After that, the present inventors further investigated the improvement, and found that by blending a hindered amine compound into the above block copolymer,
A new discovery that weather resistance is dramatically improved without compromising transparency 1. , we have completed the present invention.

That is, the present invention comprises ((trans)) a polymer block mainly composed of at least two vinyl aromatic hydrocarbons and at least one polymer block mainly composed of a conjugated diene; Weight ratio with diene is 60:40-90
: 10, and (,) the molecular weight of the main vinyl aromatic hydrocarbon polymer block contained in the block copolymer is 10.000 to 5.
0,000 or (b) the molecular weight of the main vinyl aromatic hydrocarbon polymer block contained in the B block copolymer is so, o o
o and has a molecular weight of 5,000 to 35,000
A block copolymer in which the weight ratio of the vinyl aromatic hydrocarbon polymer block group A□ in the area of □ and the vinyl aromatic hydrocarbon polymer block group A having a molecular weight of s o, o o o or more is □A or more , based on 100 parts by weight, (B) at least one group represented by the following formula [E] in the molecule C\NH[l]/CR2H.

(In the formula, R11R, I R8 and R4 represent the same or different alkyl groups.) A block copolymer composition containing: l
0% or more.

The heat-shrinkable films and sheets of the present invention (hereinafter referred to as heat-shrinkable films, etc.) have excellent low-temperature shrinkability, so they can be used to package articles that may deteriorate or deform if heated at high temperatures for long periods of time in the shrink-wrapping process. For example, the heat-shrinkable film of the present invention is suitable for packaging fresh foods and plastic molded products, and has excellent weather resistance, so it is suitable for packaging products that are exposed to sunlight during transportation, storage, or use. Available. Furthermore, when the hindered amine compound and the compound component (C) described in detail later are combined in the present invention, the heat-shrinkable film of the present invention has excellent environmental damage resistance. It has the feature that it is difficult to break down even if the coated article is left in an outdoor environment with severe temperature changes. In particular, if the article to be coated is metal,
Characteristics, such as porcelain, glass, polyester resin, etc.
For example, in cases where the film is composed of particles with extremely different coefficients of thermal expansion and water absorption, conventional heat-shrinkable films have the drawback of poor environmental damage resistance after coating, and the film easily cracks. However, when the heat-shrinkable film of the present invention is used, there is no such problem and it can withstand being left in the natural environment for a long time. Therefore, the heat-shrinkable film of the present invention can be suitably used as a decorative or advertising label, or as a material for protecting easily breakable containers such as glass pins, by taking advantage of such advantages.

The present invention will be explained in detail below.

The block copolymer of component (A) used in the present invention comprises at least two vinyl aromatic hydrocarbon-based polymer blocks (hereinafter referred to as block A) and at least one
It is a block copolymer having a polymer block (hereinafter referred to as block B) mainly composed of conjugated dienes. Here, block A means that the content of vinyl aromatic hydrocarbons is 5
More than 0% by weight, preferably more than L10% by weight of polymer blocks. Further, a polymer block mainly composed of a conjugated diene is a polymer block having a conjugated diene content of 50% by weight or more, preferably 70% by weight or more. If there is a vinyl aromatic hydrocarbon randomly copolymerized with the conjugated diene in these polymer blocks, this vinyl aromatic hydrocarbon may be uniformly distributed in the polymer chain or tapered. The vinyl aromatic hydrogen content of the block copolymer used in the present invention may be distributed in the form of 60 to 90! i Keiji, preferably 6
It is 5 to 85% by weight, more preferably 68 to 78% by weight. When the content of vinyl aromatic hydrocarbon is less than 60% by weight, the tensile strength and rigidity are poor and the film is unsuitable as a heat-shrinkable film. Moreover, if it exceeds 90% by weight, it is not preferable because impact resistance is poor.

Furthermore, the block copolymer used in the present invention is characterized in that (a) the main vinyl aromatic hydrocarbon polymer block contained in the block copolymer has a molecular weight of 10,000 to 50,000;
, preferably from 15,000 to 50,000 (referred to as block copolymer (a)) or (b) the molecular weight of the main vinyl aromatic hydrocarbon polymer block contained in the U block copolymer. s o, o o
.

more than 60,000 to 200,000, preferably a vinyl aromatic hydrocarbon polymer block group A1 with a molecular weight in the range of 5,000 to 35,000, and a vinyl aromatic hydrocarbon polymer block group A1 with a molecular weight of 50,000 or more. A block copolymer (referred to as block copolymer (b)) whose weight ratio with the hydrogen polymer block group A2 is IA or more, preferably lA or more. In the block copolymer (a), the molecular weight of the main vinyl aromatic hydrocarbon polymer block is i o, o
If it is less than 0, the tensile strength and rigidity will be poor, so it is not preferable, and if it is more than 50,000, the requirements for block copolymer (b) must be met. In the block copolymer (b), if the weight ratio of the vinyl aromatic hydrocarbon polymer block groups A1 and A is less than IA, it is not preferable because low-temperature shrinkability deteriorates.

In addition, in the present invention, the molecular weight of the vinyl aromatic hydrocarbon polymer block contained in the block copolymer is determined by
A method of oxidative decomposition using butyl-hydronochloride oxide (L, M, KOLTHOFF, etaA, ).

J, Po1)'m-5ci-eng, 429 (19
GPC of a vinyl aromatic hydrocarbon polymer block obtained by decomposition by the method described in 46) or the decomposition method with ozone (Proceedings of the Society of Polymer Science, Vol. 29, No. 9, p. 055).
(Refers to the molecular weight determined from the gel permeation chromatogram in Gel-permeation chromatography measurement.) The molecular weight of the main vinyl aromatic hydrocarbon polymer block contained in the block copolymer is the molecular weight of the gel permeation chromatogram. It refers to the molecular weight determined from the position of the maximum peak in a migration chromatogram.

The weight ratio of the vinyl aromatic hydrocarbon polymer block groups A1 and A2 is such that the molecular weight in the gel/combination chromatogram is 5.000 to as, and the peak area in the ooo region and the molecular weight are 50,000 or more. It is the relative ratio of the peak areas in the region.

In the block copolymer used in the present invention, the molecular weight of block B is not particularly limited, but generally the number average molecular weight is 500 to 1,000, preferably 1,000 to 1,000.
ioo, ooo. Moreover, the number average molecular weight of the block copolymer as a whole is 20,000 to 500,000.
, preferably so, o o o to ao o, o
It's o o.

In a particularly preferred block copolymer in the present invention, the block A constituting the block copolymer is substantially composed of a vinyl aromatic hydrocarbon homopolymer, and the block B
is a block copolymer substantially composed of a conjugated diene homopolymer.

Here, a block polymer in which block A is substantially composed of a vinyl aromatic hydrocarbon homopolymer and block B is substantially composed of a conjugated diene homopolymer is defined as It means a block copolymer with a small amount of vinyl aromatic hydrocarbon randomly copolymerized with a diene, and specifically, the overall non-block rate of the block copolymer represented by the following formula is 15m11%.
Hereinafter, preferably a block copolymer with a weight of 10 weight or less, more preferably a block copolymer with a weight of 5 weight or less.

The weight of the vinyl aromatic hydrocarbon polymer block in the block copolymer can be determined by decomposing and quantifying the block copolymer using the aforementioned oxidative decomposition method, ozonolysis method, or the like. It is preferable to use such a block copolymer because it provides a material with excellent rigidity.

In addition, in the present invention, a block copolymer outside the range specified in the present invention may be mixed with the block copolymer specified in the present invention as necessary, but the blending amount is 5.
It should be less than 0% by weight, preferably less than 30% by weight, more preferably less than 10% by weight.

The block copolymer used in the present invention can basically be produced by conventionally known methods, such as those disclosed in Japanese Patent Publication No. 36-19286, Japanese Patent Publication No. 43-14979, Japanese Patent Publication No. 49-3.
The methods described in Japanese Patent Publication No. 6957, Japanese Patent Publication No. 48-2423, Japanese Patent Publication No. 48-4106, etc. are available, but the molecular weight of the vinyl aromatic hydrocarbon polymer block,
The production conditions must be set so that the quantity relationship and vinyl aromatic hydrocarbon content are within the range specified by the present invention.

All of the above-mentioned known methods involve block copolymerizing a conjugated diene and a vinyl aromatic hydrocarbon using an anio/polymerization initiator such as an organolithium compound in a solvent such as a hydrocarbon solvent.

In the present invention, the polymer structure has the general formula (a)
(A B)1+x (B) A%B-A)n (C) B + A-B)1+x (In the above formula, A is a polymer block mainly composed of vinyl aromatic hydrocarbons, and BL conjugated diene It is a polymer block mainly composed of.

The boundary between block A and block B does not necessarily have to be clearly distinguished. n is an integer of 1 or more, preferably 1 to 3
) is an integer of) or the general formula, (d) B-A9B] 9X ()) ((A-B+iA excitation or any of these block copolymers. Mixtures can be used.

In the present invention, vinyl aromatic hydrocarbons include styrene, O-methylstyrene, p-methylstyrene, p-
There are tert-butylstyrene, 1,3-di1methylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene, etc., but the most common one is styrene. The above may be used in combination. The conjugated diene is a diolefin having a pair of conjugated double bonds, for example, 1
．． 3-butadiene, 2-methyl-1,3-butadiene (
Isoprene L2,3-dimethyl-1,3-butadiene,
1,3-pentadiene, 1,3-hexadiene, etc., but particularly common ones are 1,3-butadiene,
Isoprene is mentioned. These may be used not only alone, but also as a mixture of two or more.

The block copolymer used in the present invention may be subjected to hydrogenation, halogenation, hydrogen halogenation, epoxidation, or chemical reaction within a range that does not impair its basic properties, such as low-temperature shrinkability and rigidity. Hydroxyl group, thiol group, nitrile group,
Modifications such as introduction of functional groups such as sulfonic acid groups, carboxyl groups, and amino groups may also be performed.

In the present invention, a low molecular weight vinyl aromatic hydrocarbon polymer or copolymer (component (D)) is added to the block copolymer (component (A)) for the purpose of improving low-temperature stretchability and low-temperature shrinkability. May be blended. In addition, for the purpose of further improving low-temperature stretchability, low-temperature shrinkability, and rigidity, the block copolymer may be combined with the component (D) and a relatively high molecular weight vinyl aromatic hydrocarbon polymer or copolymer (component (E)). ) may also be blended. Furthermore, component (E) alone may be blended into the block copolymer for the purpose of improving rigidity.

If necessary, the vinyl aromatic hydrocarbon polymer or copolymer of components (D) and (E) used in the present invention may be a homopolymer or copolymer of the above-mentioned vinyl aromatic hydrocarbon monomer. , the above-mentioned vinyl aromatic hydrocarbon monomers and other vinyl monomers, such as evaporated ethylene, propylene, butylene, vinyl chloride, vinylidene chloride, vinyl acetate, acrylic esters such as methyl acrylate, methacrylic esters such as methyl methacrylate, Copolymers with acrylonitrile etc. are included. Particularly preferred is styrene/
A copolymer of styrene and α-methylstyrene, and a copolymer of styrene and methyl methacrylate.

The number average molecular weight of the low molecular weight vinyl aromatic hydrocarbon polymer or copolymer of component (D) used in the present invention is 20,
000 or less, preferably 200 to 10,000, more preferably 300 to 5,000. Number average molecular weight is 2
If it exceeds o, o o o, the effect of improving low-temperature shrinkability is lost, which is not preferable. Particularly preferred are those having a number average molecular weight of 300 or more and less than 500, and such low molecular weight polymers or copolymers have an extremely good effect of improving low-temperature shrinkage properties. When blending the low molecular weight vinyl aromatic hydrocarbon polymer or copolymer as component (D), 5 to 100 parts by weight of the block copolymer as the component is used.
Parts by weight, preferably 10 to 70 parts by weight, more preferably 15 to 55 parts by weight.

The number average molecular weight of the relatively high molecular weight vinyl aromatic hydrocarbon polymer or copolymer used as component (E) in the present invention is 30,000 or more, preferably 50,900 to 1
,000,000, more preferably so, o o o
~soo, ooo.

If the number average molecular weight of component (E) is less than ao, oo, it is not preferable because the effect of improving rigidity is not sufficient.

The blending amount of the vinyl aromatic hydrocarbon polymer or copolymer as component (B) is the same as the block copolymer io of component (A).

5 to 80 parts by weight, preferably 10 to 6 parts by weight
0 parts by weight, more preferably 15 to 45 parts by weight.

Component (B) used in the present invention includes, for example, a H/D amine compound represented by the following general formula ([) or [■].

(In the formula, R□ and R2 are the same or different carbon atoms 1-1
2 shows the alkyl group. t represents 1, 24 or 3. R
When t=1, 3 represents a monovalent acyl group, alkyl group, cycloalkyl group, aryl group, or N-substituted carbamoyl group, and when t=2, it represents a diacyl group, alkylene group, or aryl group.
- Represents a dialkylene group, dicarbonyl group or dicarbonyl group, and when t=3 represents a triazyl group. ) (wherein m represents 0 or l, n ld represents 1 or 2, R4 and R6 are the same or different, and represent a straight or branched alkyl group having 1 to 12 carbon atoms, or R4 and R6 together with the carbon atoms of the ring to which they are bonded form a cycloalkyl group having 5 to 12 carbon atoms, and R6 is hydrogen or a straight or branched alkyl group having 1 to 12 carbon atoms; or a Schiff straight-chain or branched alkyl group having 5 or 6 carbon atoms; the molecular chain alkyl group is unsubstituted or substituted with a halogen, cyan group, or hydroxyl group; or a sulfur atom may be present. R@ also represents an alkyl group having 7 to 12 carbon atoms, an alkenyl group having 3 to 12 carbon atoms, or a cycloalkyl group having 5 to 2 carbon atoms. ) R represents hydrogen, a monovalent or divalent hydrocarbon residue having 1 to 21 carbon atoms, and the hydrocarbon residue is unsubstituted or substituted with a halogen, cyano group or hydroxyl group. or one or more oxygen atoms or sulfur atoms may be present; ), where Y is hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, an alkenyl group or alkynyl group having 3 to 12 carbon atoms, and an aralkyl group having 7 to 13 carbon atoms. group or group -CH*CH
(OH) R@ (wherein, R8 is hydrogen or has 1 carbon atom
~4 alkyl group or phenyl group),
When A represents 10- (in the formula, q represents 1 or 2) or -C-0- represents 1, and n represents 1, and R2 represents p = 2, the formula (1)
When representing a group, X represents -CNH-. However, when A represents 10-, R7 does not represent hydrogen, and A represents )NR, and m represents 1. n is 2,
When X represents -C-, Ra may be hydrogen. ) In the present invention, the piperidine derivative represented by the above general formula [10] is effective.

Examples of the compound represented by the general formula (n) include the following compounds.

■4-acetoxy-2,2,6,6-titramethylpiperidine■4-stearoyloxy-2,2,6,6-tethomethylpiperidine ■4-acryloyloxy-2,2,6,6-titramethylpiperidine■ 4-benzoyloxy-2,2,6,6-titramethylpiperidine■4-Cp-chlorobenzoyloxy)-2,2,6,
6-Titramethylbiveridine ■ 4-Methoxy-2,2,6,6-titramethylpiperidine ■ 4-Cyclohexyloxy-2,2,6,6-titramethylpiperidine ■ 4-Benzyloxy-2,2,6. 6-Titramethylpiveridine■4-Phenoxy2,2,6,6-Titramethylpiveridine [Phase]4-(phenylcarbamoyloxy)-2,2.
6,6-titramethylbiperidine■Bis(2,2,6,6-tetramethyl-4-piperidyl)oxalate@His(2,2,6,6-titramethyl-4-piperidine)malonate 0bis(2, 2,6,6-tetramethyl-4-piperidyl) adipate 0 bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate [phase] bis(2,2,6,6-tetramethyl-4 -piperidyl) terephthalate [phase] 1,2-bis(2,2,6,6-tetramethyl-
4-piperidyloxy)-ethane0α・α′-bis(2,2,6,6-titramethyl-4
- Hihe17,)-ruoxy)-p-xylene0bis(
2,2,6,6-teto2methyl-4-piperidyl)hexamethylene-1,6-dicarbamate [phase] Tris(2,2,6,6-tetramethyl-4-piperidyl)benzene-1,3・5-) 17 carboxylate [phase] Tetra(2.2.6.6-tetramethyl-4-piperidyl)butane-1.2.3.4-tetracarboxylate The above hindered amine compound is composed of component (A ) to 5 parts by weight, preferably 0.01 to 2 parts by weight, per 100 parts by weight of the block copolymer.

When the blending amount of the hindered amine compound is less than o and oos parts by weight, the effect of improving weather resistance is insufficient, and on the other hand, even when the blending amount exceeds 5 parts by weight, no significant improving effect is observed. Incidentally, commercially available hindered amine compounds include Sanol LS-622, LS-770, and LS-9.
44 (Sankyo Co., Ltd., Ciba-Geigi Co., Ltd.), mark LA-5
7 (Adeka Argus), and these companies can be used as the component (B) of the present invention.

In the present invention, in addition to the hindered amine compound of component (B), a benzophenone compound and/or a benzotriazole compound may be used in combination. When such compounds are used in combination, the effect of improving weather resistance is exhibited mutually, and even if the amount of the hindered amine compound compounded is reduced, a product having good weather resistance can be obtained. When these compounds are used in combination, the amount of the hindered amine compound (B) to 100 parts by weight of the block copolymer (A) is o, oos to iz Teito, preferably 0.01 parts by weight. ~0.8 parts by weight, benzophenone compound and/or benzo) IJ azole compound 0.05~
Suitable amounts include 1 part by weight, preferably 0.1 to 0.8 parts by weight.

Examples of benzophenone compounds and/or benzotriazole compounds that can be used in the present invention include the following.

@2,4-dihydroxybenzophenone [phase] 2-hydroxy-4-methoxybenzophenone @2-hydroxy-4-n-octoxybenzophenone [stock] 2-hydroxy-4-n-dotecyloxybenzophenone [phase] 2-hydroxy-4- Benzyloxy-enzophenone [phase] 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole@2-(2'-hydroxy-af, 5'-di-t-butylphenyl)-S-chloro -penztriazole [phase] z-(2'-hydroxy-3'-t-butyl-5
'-methylphenyl)-5-chloro-benzotriazole@12-(2'-hydroxy-al, s/-di-t-amylphenyl)-benzotriazole@12-(2'-hydroxy-af, s+-di -t-butylphenyl)-benzotriazole@2-(2'-hydroxy-5'-5-butylphenyl)benzotriazole@2-(2'-hydroxy-5'-octylphenyl)
-Benzotriazole Furthermore, the floc copolymer composition lc used in the present invention is
p-phenylenediamine compounds, quinoline compounds,
By blending as component (C) at least one compound selected from dithiocarbamic acid compounds, i,a-bis(dimethylaminopropyl)-2-thiourea, and wax, it improves durability, for example under outdoor conditions. Environmental damage resistance can be further improved. Examples of p-phenylenediamine compounds include diaryl-p-7enylenediamine, N,N'-diphenyl-p-phenylenediamine, N-phenyl-N'-impropyl-p-phenylenediamine, N,N'- Di-2-naphthyl-p-phenylenediamine, N (3-meta2I).

yloxy-2-hydroxypropyl)-N'-phenyl-p-phenylenediamine, alkylated diphenylamine, N-7enyl-N'-isooctyl-p-phenylenediamine, N-7enyl-N'-(i,a-dimethylbutyl )-p-phenylenediamine, N,N'-bis(1-methylheptyl)-p-phenylenediamine, mixed diaryl-p-phenylenediamine, and the like. Examples of quinoline compounds include 2,2,4-)dimethyl-1,2-dihydro-6-nitoxyquinoline, poly(2,2,4-)limethyl-1,2-)dimethyl-1
, 2-dihydroquinoline) and the like. Examples of dithiocarbamic acid compounds include nickel diethyldithiocarbamate and nickel dibutyldithiocarbamate. Component (C) is generally 2 to 0.0 parts per 100 parts of the block copolymer of component (A).
0.01 part by weight, preferably 1 to 0.005 part by weight.

In addition, the block copolymer composition used in the present invention may contain lubricants, antistatic agents, various stabilizers, plasticizers,
A softener and the like can be added.

The lubricants include higher fatty acids having 10 to 26 carbon atoms, amides of higher fatty acids having 10 to 26 carbon atoms, ethylene bis fatty acid amides such as ethylene bis stearamide, higher alcohols, finely powdered inorganic fillers, and waxes. Antistatic agents include glycerin fatty acid ester, sorbitan fatty acid ester, glopylene glycol fatty acid ester, citric acid stearyl ester, pentaerythritol fatty acid ester, polyglycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyoxyethylene rubitan. Fatty acid ester, polyethylene glycol fatty acid ester, polypropylene glycol fatty acid ester, polyoxyethylene fatty alcohol ether, polyoxyethylene alkylphenyl ether, N,N bis(2-hydroxyethyl) fatty amine,
Anionic surfactants such as condensation products of fatty acids and jetanol, block polymers of polyoxypropylene and polyoxyethylene, polyethylene glycol, and polyethylene glycol merzenesulfonate can be used. These lubricants and antistatic agents are component (A)
It is generally used in an amount of 0.1 to 2 parts by weight based on 100 parts of the block copolymer.

The block copolymer composition used in the present invention can be produced by any conventionally known blending method. For example, melt-kneading methods using common mixers such as open rolls, intensive mixers, internal mixers, co-kneaders, continuous kneaders with twin-screw rotors, extruders, etc.; A method of removing the particles by heating is used.

In order to obtain a heat-shrinkable stretched film etc. from the above-mentioned block copolymer composition, the methods conventionally used to impart heat-shrinkability to films made of vinyl chloride resin, etc. are basically the same. However, the resulting heat-shrinkable film etc. has a heat shrinkage rate of 10% or more at 90°C, preferably 1.
It should be between 5 and 90%, more preferably between 20 and 70%.

If the heat shrinkage rate at 90℃ is less than 10%, low-temperature shrinkability is poor, so it is necessary to adjust the shrink packaging process to a high temperature and uniformity, or to heat it for a long time, which may cause deterioration or deformation at high temperatures. This is undesirable because it becomes impossible to package such items and shrink-wrapping processing capacity decreases. In the present invention, the heat shrinkage rate at 90°C refers to the rate at which an l-axis stretched or biaxially stretched film, etc. is immersed for 5 minutes in a heating medium such as 90°C hot water, silicone oil, or glycerin that does not inhibit the properties of the molded product. This is the heat shrinkage rate in each stretching direction of the molded product when

In order to obtain a heat-shrinkable uniaxially or biaxially stretched film etc. from the block copolymer composition described above, the block copolymer composition is molded into a flat or tubular shape from an ordinary T-die or annular die at a temperature of 150 to 250%. °C, preferably 170~
Extrusion molding is carried out at 220° C., and the obtained unstretched product is subjected to l-axis stretching or i, l: biaxial stretching. □For example, in the case of l-axis stretching,
If it is in the form of a film or sheet, it is stretched in the extrusion direction using a calender roll or the like, or in a direction perpendicular to the extrusion direction using a tensile press, and if it is in the form of a tube, it is stretched in the extrusion direction or circumferential direction of the tube. In the case of biaxial stretching, in the case of a film or sheet, the extruded film or sheet is stretched in the longitudinal direction with a metal roll, etc., and then stretched in the transverse direction with a tenter, etc., and in the case of a tube, the extruded film or sheet is stretched in the longitudinal direction with a tenter, etc. The tubes are stretched simultaneously or separately in the circumferential direction of the tube, that is, in the direction perpendicular to the tube axis.

In the present invention, it is preferable to stretch at a stretching temperature of 60 to 120°C, preferably 80 to ioC, and a stretching ratio of i, s to 8 times, preferably 2 to 6 times, in the machine direction and/or the transverse direction. If the stretching temperature is less than 60°C, breakage will occur during stretching and the desired heat-shrinkable film will be less than 120°C.
If the temperature exceeds .degree. C., it is difficult to obtain a material with good low-temperature shrinkability. The stretching ratio is selected within the above range to correspond to the shrinkage rate required depending on the application, but if the stretching ratio is less than 1.5 times, the heat shrinkage rate is low and it is not suitable for heat-shrinkable packaging. A stretching ratio of more than 8 times is not preferable in terms of stable production in the stretching process. In the case of biaxial stretching, the stretching ratios in the machine direction and the transverse direction may be the same or different. After the l-axis stretching or the biaxial stretching, the heat-shrinkable film etc. is then immediately heated to 60 to 1
05°C, preferably 80-95°C for a short time, e.g.
It is also possible to carry out a heat treatment for 60 seconds, preferably 10 to 40 seconds, to prevent natural shrinkage at room temperature.

The l-axis stretched or biaxially stretched heat-shrinkable film of the present invention has a tensile modulus of elasticity of 15.00@K in the stretching direction.
It is preferable for the heat-shrinkable packaging material to have f/i or more, preferably 7,000 K4/ct& or more, more preferably so, ooo h/d or more. The tensile modulus in the stretching direction is 5. If it is oooKf/- or more, it is preferable because normal packaging can be performed without causing sagging in the shrink packaging process.

In the heat section of the present invention obtained in this way? The thickness of the J-type film is generally adjusted to be in the range of 10 μm to 1 ms.

When the l-axis stretched or biaxially stretched film of the present invention is used as a heat-shrinkable packaging material, the temperature is 150 to 300°C, preferably 180 to 250°C, in order to achieve the desired heat shrinkage rate.
It can be heat-shrinked by heating at a temperature of from several seconds to several minutes, preferably from 1 to 60 seconds, more preferably from 2 to 30 seconds.

The XL-stretched or biaxially-stretched heat-shrinkable film of the present invention is superior in terms of hygiene compared to conventional vinyl chloride resin-based films, and its properties can be utilized for various purposes, such as fresh food, frozen food, etc. It can be used for packaging food, confectionery, clothing, stationery, toys, etc. Particularly preferred applications include -1. After printing characters or designs on a uniaxially stretched film of the block copolymer composition defined in the present invention, it can be printed on the surface of a packaged object such as a plastic molded product, metal product, glass container, or porcelain. It can be used as a material for so-called heat-shrinkable labels, which are used in close contact with each other by heat-shrinking. When used as a heat-shrinkable label material, 9 in the direction perpendicular to the stretching direction.
Thermal shrinkage rate at 0°C is less than 10 inches, preferably -5- or less,
More preferably, the number is 3 or less.

Examples of the present invention will be shown below to explain the present invention in more detail, but it goes without saying that the content of the present invention is not limited to these Examples.

Examples 1 to 15 and Comparative Examples 1 to 6 Using n-butyllithium as a catalyst, styrene-butadiene block copolymer A having a (B-8) II type structure and a styrene content of 80% by weight was produced. did.

The molecular weight of the main polystyrene blocks contained in this block copolymer A is 25,000, and the non-blocking rate is 3.
It was Chi. In addition, 0.5 parts by weight of Irganox 1076 (Ciba Geigi) was added to block copolymer A as a stabilizer based on 100 parts by weight of the block copolymer.

Next, after blending the additives shown in this block copolymer AKFt1, it was formed into a sheet using a 25-ply φ extruder, and then uniaxially stretched to 4 times its size using a tenter to form a film with a thickness of about 60μ. Created. At this time, the minimum temperature inside the tenter at which the uniaxially stretched film can be stably produced without breaking during stretching (hereinafter referred to as the minimum stretchable temperature) is approximately 90°C.
Met.

The physical properties of each of the uniaxially stretched films obtained were similar to those of Film 2, and the films exhibited good rigidity, impact resistance, and low-temperature shrinkability. Incidentally, the heat shrinkage rate of each of these films at 90° C. in the direction orthogonal to the stretching direction was 3% or less.

Next, the weather resistance of the heat-shrinkable film obtained above was investigated.
It is shown in Clothing 1. As a result, it was revealed that the heat-shrinkable film of the present invention has extremely excellent weather resistance. In addition, when the environmental damage resistance of each of the heat-shrinkable films mentioned above was investigated, it was found that the environmental damage resistance could be improved by using the compound contained in component (C) described in the present invention. found.

Margin below Table 1 (Continuation of clothing 1) (Note 1) The compound number is the number in the above specification.

However, ■ to ■ are the following compounds.

■; Sanol L8944 (Sankyo Co., Ltd.) ■; N-phenyl-N'-isopropyl-p-phenylenediamine ■; N-phenyl-N'-(1,3-dimethylphthyl)
-p-phenylenediamine (2): 6-nitoxy1,2-dihydro-2,2,4-trimethylquinoline (Note 2) The amount added is shown based on 100 parts by weight of the block copolymer.

(Note 3) The tensile elongation at break of each sample after the 100-hour weather meter irradiation test was compared with the tensile elongation at break of each sample before the test, and the quality of weather resistance was determined based on the retention rate.

Equipment used: Atlas Sunshine Weather Meter (only irradiates light) Judgment criteria: A: Retention rate of 90- or more B: Retention rate of 70 inches or more, less than 90 inches C: Retention rate of 30% or more, less than 70 inches D = Retention rate 10% or more, less than 30% E: Retention rate less than 10 inches (Note 4) Each stretched film was slit to match the size of a glass bottle, sealed, mounted on a glass bottle, and further heated and shrunk with hot air. . The film-coated product was left outdoors in a natural environment, and its environmental damage resistance was measured by the number of days in the trench that microcracks and cracks appeared in the coated film.

Judgment criteria: 0211 days or more ○: 4 to 10 days X: 3 days or less Margin Table 2 (Notes) Based on JIS K-6732 (Note 6)
Based on JIS P-8134 (Note 7) JIS
Based on K-6714 (Note 8) The film was immersed in silicone oil at 90°C for 5 minutes, and calculated using the following formula.

t-t' Thermal shrinkage rate (ch) = -X 100 t: Length before shrinkage t': Length after shrinkage Comparative Example 7 It has the same polymer structure as block copolymer A, and the styrene content is A 95% by weight styrene-butadiene block copolymer B was produced. Next, the same additives as in Example 13 were blended to produce a uniaxially stretched film. However, the film was very brittle and easily cracked during film formation and winding, making it impossible to obtain a good film.

Comparative Example 8 A styrene-butadiene block copolymer C having the same polymer structure as block copolymer A and having a styrene content of 50% by weight was produced. Next, the same additives as in Example 13 were blended to form an l-axis stretched film. However, this film had poor rigidity and could not be automatically attached to a container.

Examples 16 to 18 and Comparative Example 9 Block copolymers having the polymer structure, styrene content, etc. shown in Cloth 3 were produced using n-butyllithium as a catalyst and according to a conventional method.

After adding the additives shown in Table 3 to these copolymers, they were formed into a sheet using a 251IJIφ extruder, and then uniaxially stretched 8 times using a tenter to a thickness of approximately 50 mm.
At this time, the temperature inside the tenter was set to the lowest temperature at which each block copolymer composition could be stretched.

Next, the performance of heat-shrinkable films of each block copolymer composition was investigated, and the results are shown in Cloth 3. In addition, Examples 16 to 1B
The transparency of the heat-shrinkable films was good, and the Hare was 5% or less in all cases.

Biaxially stretched films were obtained from the same block copolymer compositions as in Examples 19 to 21 and Examples ta and 16.18 by the inflation method. The stretching temperature was approximately the same as in the case of 1@stretching. Characteristics of the obtained film 4
It was shown to.

Margin below Table 4

Claims (1)

[Claims] 1. (A) Consisting of at least two vinyl aromatic hydrocarbon-based polymer blocks and at least one conjugated diene-based polymer block; Weight ratio with conjugated diene is 60:40-90
: A block copolymer that is 1G, and (a) the molecular weight of the main vinyl aromatic hydrocarbon polymer block contained in the #block copolymer is 10.000 to s.
o, o o o or (b) a block copolymer in which the molecular weight of the main vinyl aromatic hydrocarbon polymer block contained in the block copolymer is s o, o o
o, and the molecular weight is 5,000 to B 5,000
vinyl aromatic hydrocarbon polymer block group A in the area of
and a vinyl aromatic hydrocarbon polymer block group A2 having a molecular weight of so, ooo or more, and a block copolymer having a weight ratio of V6 or more, (E) at least one of the following in the molecule: A block copolymer containing 0.005 to 5 parts by weight of a hindered amine compound having a group represented by the formula CI) (wherein R, , R, , R, and R4 represent the same or different alkyl groups) The combined composition is subjected to l-axis stretching or 2
A heat-shrinkable film or sheet that is axially stretched and has a heat shrinkage rate of 10- or more at 90°C in the stretching direction? , (A) consisting of at least two polymer blocks mainly composed of vinyl aromatic hydrocarbons and at least one polymer block mainly composed of conjugated dienes, with a weight ratio of vinyl aromatic hydrocarbons and conjugated dienes of 60: 40-90
: 10, and (a) the molecular weight of the main vinyl aromatic hydrocarbon polymer block contained in the block copolymer is io, ooo~
50,000, or (b) the molecular weight of the main vinyl aromatic hydrocarbon polymer block contained in the block copolymer is 150,000.
and the weight ratio of the vinyl aromatic hydrocarbon polymer block group AI with a molecular weight in the range of 5,000 to 35,000 and the vinyl aromatic hydrocarbon polymer block group A with a molecular weight of 50,000 or more. (B) At least one group represented by the following formula [■] in the molecule (wherein R1, R,, R3 and R4 are A block copolymer composition containing 0.005 to 5 parts by weight of a hindered amine compound having the same or different alkyl groups is stretched along the l-axis, and the heat shrinkage rate at 90°C in the stretching direction is 10. % or more of the heat-shrinkable film component (B) for labels has the formula [■] (wherein R1 and R3 represent the same or different alkyl groups. t represents 1,2''!P or 3). When Rsl'1t = 1, it represents a monovalent acyl group, alkyl group, cycloalkyl group, aryl group, or N-substituted carbamoyl group, and when t = 2, it represents a diacyl group, alkylene group, arylene dialkylene group, dicarbonyl group. or a dicarbamoyl group, and when t=3, a triazyl group.
) is represented by formula (II) (wherein R1 and R8 represent the same or different alkyl groups. t represents 1.2 or 3. When t=1, R3 represents a monovalent acyl group, an alkyl group, a cyclo It represents an alkyl group, an aryl group or an N-substituted carbamoyl group; when t=2 it represents a diacyl group, an alkylene group, an arylene dialkylene group, a dicarbonyl group or a dicarbamoyl group; when t=3 it represents a triazyl group. ) The heat-shrinkable film for labels according to claim 2, which is a piperidine derivative represented by