JP5506364B2 - Heat-shrinkable molded body - Google Patents

Description

  The present invention relates to a heat shrinkable molded article having excellent UV discoloration resistance, transparency, low temperature shrinkage characteristics, and impact resistance.

  Examples of heat-shrinkable molded products used for shrink-wrapping, shrink-bound packaging, shrink labels and cap seals include polyvinyl chloride (PVC), styrene-butadiene block copolymer (SBS), and polyethylene terephthalate (PET). A heat-shrinkable film (hereinafter referred to as a shrink film) produced by melt-extrusion and then stretched and rapidly cooled is known and widely used in the industry.

  Among these, although PVC has excellent practical characteristics and cost as a shrink film, the problem of generating toxic gas containing chlorine when incinerated after disposal has been pointed out. It has been replaced with SBS and PET, which do not have such incineration pollution problems.

  On the other hand, SBS and PET do not have incineration pollution problems, but have some problems as shrink films compared to PVC. As a typical example, SBS has low room temperature rigidity (elastic modulus), and PET has problems such as insufficient impact resistance depending on the application. Yes.

  Polycarbonate is an example of a non-PVC material having a high elastic modulus at room temperature and a high tensile elongation at break. Polycarbonate has excellent impact resistance and optical properties in addition to elastic modulus and elongation at break, and is considered to have physical properties that are not inferior to conventional products as a shrink film.

  In addition, shrink films are often used for food, medicine, cosmetics, paper or plastic containers that enclose them, capacitors, batteries, etc., and do not change these objects. It is necessary to shrink under mild heating conditions. Specifically, it is shrunk by heating at 70 to 140 ° C., usually 80 to 100 ° C. within 1 minute, in many cases from several seconds to several tens of seconds using steam, hot air, hot water, silicone oil or the like. Therefore, as one simple indicator of whether or not a shrink film has practical shrink characteristics, when the film is immersed in silicone oil at 100 ° C., which is a typical actual temperature, for 20 seconds, It is important whether or not it has a shrinkage rate.

  In view of this background, Patent Document 1 discloses a shrink film made of an aromatic polycarbonate resin, and Patent Document 2 discloses a shrink film / tube formed by adding a plasticizer to polycarbonate.

JP-A-60-245539 JP 2004-339525 A

However, since the shrink film disclosed in Patent Document 1 does not start to shrink unless heated to a temperature higher than 140 ° C., it is practically sufficient in terms of content protection and energy consumption. Is hard to say.

  In addition, in the shrinkable film tube disclosed in Patent Document 2, the temperature at which shrinkage starts is lowered by blending a plasticizer, but depending on the use environment, the plasticizer may bleed out. In addition to impairing the temperature, there may be a problem that the temperature at which shrinkage starts increases.

  Thus, in the prior art, it has been very difficult to obtain a heat-shrinkable molded article having both low-temperature shrinkage characteristics and impact resistance, and being transparent and excellent in UV discoloration resistance.

  Accordingly, an object of the present invention is to provide a heat-shrinkable molded article excellent in UV discoloration resistance, transparency, low-temperature shrinkage characteristics, and impact resistance in view of such problems of the prior art.

The present invention includes a structural unit (a) derived from a dihydroxy compound represented by the following general formula (2) and a structural unit (b) derived from cyclohexanedimethanol, and the proportion of the structural unit (b) is 45. The present invention provides a heat-shrinkable molded article characterized by using a resin composition (X) containing an aliphatic polycarbonate resin (A) in an amount of from mol% to 80 mol%.

  According to the present invention, it is possible to provide a heat-shrinkable molded article excellent in UV discoloration resistance, transparency, low-temperature shrinkage characteristics, and impact resistance.

  Hereinafter, a heat-shrinkable molded article as an example of an embodiment of the present invention will be described. However, the scope of the present invention is not limited to the embodiments described below.

<Resin composition (X)>
The resin composition (X) used in the present invention is characterized by comprising an aliphatic polycarbonate resin (A) described below. The resin composition (X) may be composed only of the aliphatic polycarbonate resin (A), and may be a resin other than the aliphatic polycarbonate resin (A), as long as the characteristics of the heat-shrinkable molded article of the present invention are not impaired. An additive may be included.

<Aliphatic polycarbonate resin (A)>
As aliphatic polycarbonate resin (A) used for this invention, the structural unit derived from the dihydroxy compound which has a site | part represented by following General formula (1) in a part of structure, and the structural unit derived from cyclohexanedimethanol Polycarbonate resin containing is used.

（但し、上記一般式（１）で表される部位が−ＣＨ_２−Ｏ−Ｈの一部である場合を除く。）
すなわち、上記ジヒドロキシ化合物は、二つのヒドロキシル基と、更に上記一般式（１）の部位を少なくとも含むものを言う。

(However, the site represented by the above general formula (1) unless it is part of _-CH 2 -O-H.)
That is, the said dihydroxy compound says what contains at least the site | part of the said General formula (1) further two hydroxyl groups.

The dihydroxy compound having a site represented by the general formula (1) in a part of the structure is not particularly limited as long as a part of the molecular structure is represented by the general formula (1). Specifically, 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-methylphenyl) fluorene, 9,9 -Bis (4- (2-hydroxyethoxy) -3-isopropylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-isobutylphenyl) fluorene, 9,9-bis (4- ( 2-hydroxyethoxy) -3-tert-butylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-cyclohexylphenyl) fluorene, 9,9- (4- (2-hydroxyethoxy) -3-phenylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3,5-dimethylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-tert-butyl-6-methylphenyl) fluorene 9,9-bis (4- (3-hydroxy-2,2-dimethylpropoxy) phenyl) fluorene, etc., an aromatic group in the side chain A compound having an ether group bonded to an aromatic group in the main chain, an anhydrosugar alcohol typified by a dihydroxy compound represented by the following general formula (2), and a spiro represented by the following general formula (3) Examples of the dihydroxy compound represented by the following general formula (2) include isosorbide having a stereoisomeric relationship, such as a compound having a cyclic ether structure such as glycol. -Isomannid, include the Isoidetto. Moreover, as a dihydroxy compound represented by the following general formula (3), 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro (5.5) ) Undecane (common name: spiroglycol), 3,9-bis (1,1-diethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane, 3,9- And bis (1,1-dipropyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane.
These may be used alone or in combination of two or more.

（式中、Ｒ_１〜Ｒ_４はそれぞれ独立に、炭素数１から炭素数３のアルキル基である。）

(Wherein R _{1 to} R ₄ are each independently an alkyl group having 1 to 3 carbon atoms.)

  Of these, isosorbide is most preferable, and these may be used alone or in combination of two or more.

It is important to include a structural unit (b) derived from cyclohexanedimethanol as a structural unit other than the structural unit (a), and in particular, derived from cyclohexanedimethanol in the aliphatic polycarbonate resin (A). The proportion of the structural unit (b) is preferably 45 mol% or more and 80 mol% or less. The lower limit of the proportion of the structural unit (b) derived from cyclohexanedimethanol is more preferably 50 mol%, and even more preferably 55 mol%. By making it 45 mol% or more, sufficient shrinkage characteristics at 100 ° C. can be imparted, and a heat-shrinkable material excellent in impact resistance can be provided. On the other hand, as an upper limit, More preferably, it is 75 mol% or less, More preferably, it is 70 mol% or less. By setting it to 80 mol% or less, the heat-shrinkable molded article resulting from the aliphatic polycarbonate resin (A) can be prevented from greatly reducing heat resistance and softening, and can be used in a wide range of applications.
Of the cyclohexanedimethanol, 1,4-cyclohexanedimethanol, which is industrially easily available, is preferable.

  Furthermore, the aliphatic polycarbonate resin (A) can also contain structural units other than the structural unit (a) and the structural unit (b) as long as the object of the present invention is not impaired. The structural unit derived from the aliphatic dihydroxy compound described in the 2004/111106 pamphlet, the structural unit derived from the alicyclic dihydroxy compound described in the international publication 2007/148604 pamphlet, and the like can be given.

  Among structural units derived from the above aliphatic dihydroxy compounds, selected from the group consisting of ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. It is preferable to include a structural unit derived from at least one compound.

  Among the structural units derived from the alicyclic dihydroxy compound, those containing a 5-membered ring structure or a 6-membered ring structure are preferable. The six-membered ring structure may be fixed in a chair shape or a boat shape by a covalent bond. By including a structural unit derived from an alicyclic dihydroxy compound having a 5-membered ring structure or a 6-membered ring structure, the heat resistance of the obtained polycarbonate can be increased. The number of carbon atoms contained in the alicyclic dihydroxy compound is usually 70 or less, preferably 50 or less, more preferably 30 or less.

  Examples of the alicyclic dihydroxy compound containing the 5-membered ring structure or the 6-membered ring structure include those described in the above-mentioned International Publication No. 2007/148604, and tricyclodecane dimethanol, adamantanediol, and penta Cyclopentadecanedimethanol can be preferably exemplified, and these may be used alone or in combination of two or more.

  The glass transition temperature of the aliphatic polycarbonate resin (A) is preferably 75 ° C. or higher and 105 ° C. or lower, more preferably 80 ° C. or higher and 105 ° C. or lower, and 85 ° C. or higher and 105 ° C. or lower. Is more preferable. By using the aliphatic polycarbonate resin (A) within the range where the glass transition temperature is applied, a heat-shrinkable molded article having excellent heat resistance can be provided.

The reduced viscosity, which is an index of the molecular weight of the aliphatic polycarbonate resin (A), was prepared by using methylene chloride as a solvent and adjusting the polycarbonate concentration to 0.60 g / dl precisely at a temperature of 20.0 ° C. ± 0.1 ° C. Usually, it is 0.20 dl / g or more and 1.0 dl / g or less, preferably 0.30 dl / g or more and 0.80 dl / g or less.
When the reduced viscosity of the aliphatic polycarbonate resin (A) is excessively low, the mechanical strength at the time of molding tends to decrease. On the other hand, if the reduced viscosity of the aliphatic polycarbonate resin (A) is excessively high, the fluidity during molding is lowered, the cycle characteristics are lowered, and the distortion of the molded product tends to increase.

The aliphatic polycarbonate resin (A) can be produced by a generally used polymerization method, and may be either a phosgene method or a transesterification method in which it reacts with a carbonic acid diester. Among them, in the presence of a polymerization catalyst, a dihydroxy compound having a site represented by the general formula (1) in a part of the structure, cyclohexanedimethanol, other dihydroxy compounds used as necessary, and carbonic acid. A transesterification method in which a diester is reacted is preferred.
In the transesterification method, a dihydroxy compound having a site represented by the general formula (1) in a part of the structure, cyclohexanedimethanol, another dihydroxy compound used as necessary, and a carbonic acid diester are used as a base. It is a manufacturing method which adds an acidic substance which neutralizes this basic catalyst, and also this basic catalyst, and performs transesterification.

  Representative examples of carbonic acid diesters include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carnate, bis (biphenyl) carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, etc. Is mentioned. Of these, diphenyl carbonate is particularly preferably used.

<Aromatic polycarbonate resin (B)>
As a method for adjusting the shrinkage start temperature and heat resistance of the heat-shrinkable molded article of the present invention, the resin composition (X) can further contain an aromatic polycarbonate resin (B). The aromatic polycarbonate resin (B) may be either a homopolymer or a copolymer. The aromatic polycarbonate resin (B) may have a branched structure or a linear structure, or may be a mixture of a branched structure and a linear structure.

  As the method for producing the aromatic polycarbonate resin (B), any known method such as a phosgene method, a transesterification method, or a pyridine method may be used. As an example, a method for producing an aromatic polycarbonate resin by a transesterification method will be described below.

  The transesterification method is a production method in which a divalent phenol and a carbonic acid diester are added with a basic catalyst, and further an acidic substance that neutralizes the basic catalyst is added to perform melt transesterification polycondensation. Representative examples of the dihydric phenol include bisphenols, and 2,2-bis (4-hydroxyphenyl) propane, that is, bisphenol A is particularly preferably used. Further, part or all of bisphenol A may be replaced with other dihydric phenols. Other dihydric phenols include hydroquinone, 4,4-dihydroxydiphenyl, bis (4-hydroxyphenyl) alkanes such as bis (4-hydroxyphenyl) methane and 1,1-bis (4-hydroxyphenyl) ethane, Bis (4-hydroxyphenyl) cycloalkane such as 1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, Compounds such as bis (4-hydroxyphenyl) ether, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, etc. Alkylated bisphenols, 2,2-bis (3 , 5-dibromo-4-hydroxyphenyl) propane, halogenated bisphenols such as 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane.

  Representative examples of carbonic acid diesters include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carnate, bis (biphenyl) carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, etc. Is mentioned. Of these, diphenyl carbonate is particularly preferably used.

The viscosity average molecular weight of the aromatic polycarbonate resin (B) is usually in the range of 8,000 or more and 30,000 or less, preferably 10,000 or more and 25,000 or less, from the balance of mechanical properties and molding processability. is there. The reduced viscosity of the aromatic polycarbonate resin (B) was measured at a temperature of 20.0 ° C. ± 0.1 ° C. using methylene chloride as a solvent and the polycarbonate concentration was precisely adjusted to 0.60 g / dl. Usually, it is 0.23 dl / g or more and 0.72 dl / g or less, preferably 0.27 dl / g or more and 0.61 dl / g or less.
In the present invention, the aromatic polycarbonate resin (B) may be used alone or in combination of two or more.

  In the present invention, the aromatic polycarbonate resin (B) means that at least 50 mol% (preferably 70 mol% or more, more preferably 90 mol% or more) of one or more aromatic rings in the structural unit derived from dihydric phenol. The aromatic ring may have a substituent. Moreover, what corresponds to both an aliphatic polycarbonate resin (A) and an aromatic polycarbonate (B) shall be included in an aliphatic polycarbonate resin (A).

  As a compounding quantity of the said aromatic polycarbonate resin (B), an aromatic polycarbonate resin (B) is 1 mass% or more normally 50 mass% or less with respect to 100 mass% of the said aliphatic polycarbonate resin (A), More preferably Can be blended at a ratio of 5 mass% or more and 40 mass% or less, more preferably 10 mass% or more and 30 mass% or less. By blending the aromatic polycarbonate resin (B) within such a range, the shrinkage characteristics and heat resistance corresponding to various applications can be adjusted without impairing the excellent shrinkage characteristics and heat resistance of the heat shrinkable molded product of the present invention. can do.

<Resin other than polycarbonate resin>
The resin composition (X) used for the heat-shrinkable molded article of the present invention contains a resin other than the polycarbonate resin such as the aliphatic polycarbonate resin (A) and the aromatic polycarbonate resin (B), and an additive other than the resin. Furthermore, it can also mix | blend.

  Specific examples of resins other than polycarbonate resins that are compounded for the purpose of further improving and adjusting molding processability and various physical properties include resins such as polyester resins, polyethers, polyamides, polyolefins, polymethyl methacrylates, and core-shell types. And rubber-like modifiers such as graft-type or linear random and block copolymers. As a compounding quantity of resin other than the said polycarbonate resin, it mix | blends in the ratio of 1 mass% or more and 30 mass% or less with respect to 100 mass% of resin compositions (X) used for the heat-shrinkable molded object of this invention. It is more preferable to mix at a ratio of 3% by mass or more and 20% by mass or less, and further preferable to mix at a ratio of 5% by mass or more and 10% by mass or less.

<Heat stabilizer>
In the resin composition (X) used for the heat-shrinkable molded article of the present invention, a heat stabilizer can be blended in order to prevent a decrease in molecular weight and a deterioration in hue during molding. Examples of the heat stabilizer include phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid, and esters thereof. Specifically, triphenyl phosphite, tris (nonylphenyl) phosphite, tris (2 , 4-di-tert-butylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl Phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2-methylenebis (4,6-di-) tert -Butylphenyl) octyl phosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tributyl phosphate, triethyl Phosphate, trimethyl phosphate, triphenyl phosphate, diphenyl monoorthoxenyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate, 4,4′-biphenylenediphosphinic acid tetrakis (2,4-di-tert-butylphenyl), benzenephosphonic acid Examples thereof include dimethyl, diethyl benzenephosphonate, and dipropyl benzenephosphonate. Among them, trisnonylphenyl phosphite, trimethyl phosphate, tris (2,4-di-tert-butylphenyl) phosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2 , 6-Di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite and dimethyl benzenephosphonate are preferably used. These heat stabilizers may be used alone,
Two or more kinds may be used in combination. The blending amount of the heat stabilizer may be blended at a ratio of 0.0001% by mass or more and 1% by mass or less with respect to 100% by mass of the resin composition (X) used in the heat-shrinkable molded article of the present invention. Preferably, it is more preferable to mix | blend in the ratio of 0.0005 mass% or more and 0.5 mass% or less, and it is further more preferable to mix | blend in the ratio of 0.001 mass% or more and 0.2 mass% or less. By blending the heat stabilizer in such a range, it is possible to prevent a decrease in molecular weight or discoloration of the heat-shrinkable molded article without causing bleeding of the additive.

<Antioxidant>
The resin composition (X) used for the heat-shrinkable molded article of the present invention can be blended with an antioxidant generally known for the purpose of preventing oxidation. Examples of the antioxidant include pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-lauryl thiopropionate), glycerol-3-stearyl thiopropionate, triethylene glycol bis [3 -(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], Pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1, 3,5-trimethyl-2,4 6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, N, N-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 3, 5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 4,4′-biphenylenediphosphinic acid tetrakis (2, 4-di-tert-butylphenyl), 3,9-bis {1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} -2 , 4,8,10-tetraoxaspiro (5,5) undecane and the like. The blending amount of the antioxidant may be blended at a ratio of 0.0001% by mass or more and 1% by mass or less with respect to 100% by mass of the resin composition (X) used in the heat-shrinkable molded article of the present invention. Preferably, it is more preferable to mix | blend in the ratio of 0.0005 mass% or more and 0.5 mass% or less, and it is further more preferable to mix | blend in the ratio of 0.001 mass% or more and 0.2 mass% or less. By blending the antioxidant within such a range, oxidation deterioration of the heat-shrinkable molded article can be prevented without causing deterioration of the mechanical properties of the antioxidant bleed and the heat-shrinkable molded article.

<Lubricant>
Moreover, a lubricant can be blended for the purpose of imparting surface lubricity to the heat-shrinkable molded article of the present invention. Examples of the lubricant include higher fatty acid esters of monohydric or polyhydric alcohol, higher fatty acid, paraffin wax, beeswax, olefinic wax, carboxy group and / or
Or the olefin type wax containing a carboxylic anhydride group, silicone oil, organopolysiloxane, etc. are mentioned.

  The higher fatty acid ester is preferably a partial ester or a total ester of a monovalent or polyhydric alcohol having 1 to 20 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms. Such partial esters or total esters of monohydric or polyhydric alcohols and saturated fatty acids include stearic acid monoglyceride, stearic acid diglyceride, stearic acid triglyceride, stearic acid monosorbite, stearyl stearate, behenic acid monoglyceride, behenyl behenate, Pentaerythritol monostearate, pentaerythritol tetrastearate, pentaerythritol tetrapelargonate, propylene glycol monostearate, stearyl stearate, palmityl palmitate, butyl stearate, methyl laurate, isopropyl palmitate, biphenyl biphenate Sorbitan monostearate, 2-ethylhexyl stearate and the like. Of these, stearic acid monoglyceride, stearic acid triglyceride, pentaerythritol tetrastearate and behenyl behenate are preferably used. As the higher fatty acid, a saturated fatty acid having 10 to 30 carbon atoms is preferable. Such fatty acids include myristic acid, lauric acid, palmitic acid, stearic acid, behenic acid and the like. These lubricants may be used alone or in combination of two or more. The amount of the lubricant is preferably 0.0001% by mass or more and 1% by mass or less with respect to 100% by mass of the resin composition (X) used in the heat-shrinkable molded article of the present invention. It is more preferable to mix | blend in the ratio of 0.0005 mass% or more and 0.5 mass% or less, and it is further more preferable to mix | blend in the ratio of 0.001 mass% or more and 0.2 mass% or less. By blending the lubricant in such a range, surface lubricity can be imparted to the heat-shrinkable molded article without causing deterioration of the lubricant bleed and the mechanical properties of the heat-shrinkable molded article.

<Ultraviolet absorber, light stabilizer>
For the purpose of further improving the weather resistance of the heat-shrinkable molded article of the present invention, an ultraviolet absorber and a light stabilizer can be blended. Examples of such ultraviolet absorbers and light stabilizers include 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl)- 5-chlorobenzotriazole, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2 2,2′-methylenebis (4-cumyl-6-benzotriazolephenyl), 2,2′-p-phenylenebis (1,3-benzoxazin-4-one), and the like. The melting point of the ultraviolet absorber is particularly preferably in the range of 120 to 250 ° C. When an ultraviolet absorber having a melting point of 120 ° C. or higher is used, fogging due to gas on the surface of the molded article is reduced and improved. Specifically, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- [2'-hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2,2-methylenebis [4- (1,1 , 3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol, 2- (2-hydroxy-3,5-dicumylphenyl) benzotriazole, and other benzotriazole ultraviolet absorbers Among these, in particular, 2- (2-hydroxy-3,5-dicumylphenyl) benzotriazole, 2,2-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol is preferred. These ultraviolet absorbers and light stabilizers may be used alone or in combination of two or more. The blending amount of the ultraviolet absorber and the light stabilizer is 0.0001% by mass or more and 1% by mass or less with respect to 100% by mass of the resin composition (X) used in the heat-shrinkable molded article of the present invention. It is preferable to mix | blend, It is more preferable to mix | blend in the ratio of 0.0005 mass% or more and 0.5 mass% or less, It is further mixing | blending in the ratio of 0.001 mass% or more and 0.2 mass% or less. preferable. Addition of UV absorbers and light stabilizers within this range improves the weather resistance of heat-shrinkable molded products without causing deterioration of mechanical properties of UV absorbers, light stabilizer bleeds, and heat-shrinkable molded products. can do.

<Epoxy compound>
Furthermore, in order to further improve the hydrolysis resistance of the heat-shrinkable molded article of the present invention, an epoxy compound can be blended. Specific examples of the epoxy compound include epoxidized soybean oil, epoxidized linseed oil, phenyl glycidyl ether, allyl glycidyl ether, t-butylphenyl glycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-
Epoxycyclohexyl carboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3 ′, 4′-epoxy-6′-methylcyclohexylcarboxylate, 2,3-
Epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexylcarboxylate,
4- (3,4-epoxy-5-methylcyclohexyl) butyl-3 ′, 4′-epoxycyclohexylcarboxylate, 3,4-epoxycyclohexylethylene oxide, cyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, 3,4 -Epoxy-6-methylcyclohexylmethyl-6'-methylsiloxycarboxylate, bisphenol A diglycidyl ether, tetrabromobisphenol A glycidyl ether, diglycidyl ester of phthalic acid, diglycidyl ester of hexahydrophthalic acid, bis-epoxy Dicyclopentadienyl ether, bis-epoxyethylene glycol, bis-epoxycyclohexyl adipate, butadiene diepoxide, tetraphenylethylene epoxide, octyl epoxide Citrate, epoxidized polybutadiene, 3,4-dimethyl-1,2-epoxycyclohexane, 3,5-dimethyl-1,2-epoxycyclohexane, 3-methyl-5-t-butyl-1,2-epoxycyclohexane, octadecyl -2,2-dimethyl-3,4-epoxycyclohexyl carboxylate, N-butyl-2,2-dimethyl-3,4-epoxycyclohexyl carboxylate, cyclohexyl-2-methyl-3,4-epoxycyclohexyl carboxylate, N-butyl-2-isopropyl-3,4-epoxy-5-methylcyclohexyl carboxylate, octadecyl-3,4-epoxycyclohexyl carboxylate, 2-ethylhexyl-3 ′, 4′-epoxycyclohexyl carboxylate, 4,6 -Jimee 2,3-epoxycyclohexyl-3 ′, 4′-epoxycyclohexylcarboxylate, 4,5-epoxytetrahydrophthalic anhydride, 3-t-butyl-4,5-epoxytetrahydrophthalic anhydride, diethyl-4, 5-epoxy-cis-1,2-cyclohexyl dicarboxylate, di-N-butyl-3-tbutyl-4,5-epoxy-cis-1,2-cyclohexyl dicarboxylate and the like. Bisphenol A diglycidyl ether is preferable from the viewpoint of compatibility. As a compounding quantity of the said epoxy type compound, it mix | blends in the ratio of 0.0001 mass% or more and 5 mass% or less with respect to 100 mass% of resin compositions (X) used for the heat-shrinkable molded object of this invention. It is more preferable to mix at a ratio of 0.001% by mass or more and 1% by mass or less, and further preferable to mix at a ratio of 0.005% by mass or more and 0.5% by mass or less. By blending the epoxy compound within such a range, the hydrolysis resistance of the heat-shrinkable molded article can be improved without causing deterioration of the mechanical properties of the epoxy compound bleed and the heat-shrinkable molded article.

  In addition to the above, additives such as plasticizers, pigments, dyes, fillers and the like can be further blended in the resin composition (X) used for the heat-shrinkable molded article of the present invention.

  Next, the manufacturing method of a film and a tube is demonstrated among the heat-shrinkable molded objects of this invention. Hereinafter, these are also referred to as “the heat-shrinkable film of the present invention” and “the heat-shrinkable tube of the present invention”.

In general, "film" is a thin flat product whose thickness is extremely small compared to the length and width and whose maximum thickness is arbitrarily limited, and is usually supplied in the form of a roll. (JIS K6900) In general, the term “sheet” refers to a product that is thin according to the definition in JIS, and whose thickness is small for the length and width but flat. However, since the boundary between the sheet and the film is not clear and it is not necessary to distinguish the two in terms of the wording in the present invention, in the present invention, the term “film” includes “sheet”.

<Method for producing heat-shrinkable film>
Although it does not specifically limit about the manufacturing method of the heat-shrinkable film of this invention, The heat-shrinkable film of this invention can be made into the laminated | multilayer film of a single layer or two layers or more. A known method can be adopted as the lamination method. For example, 1) a so-called coextrusion method in which a plurality of extruders are used to connect to a single die in a feed block type or a multi-manifold type, and 2) another type of film is rolled or pressed on the surface of the unwound film. There is a film laminating method for thermocompression bonding, and 3) a so-called extrusion laminating method for extruding another type of film on the surface of the unwound film.

  A method in which the aliphatic polycarbonate resin (A) constituting the resin composition (X) and, if necessary, other resins and / or additives, etc., are introduced into the same extruder and extruded from a die to directly produce a film Alternatively, there is a method in which a pellet is produced by extruding into a strand shape and a film is produced again by an extruder. In any case, a decrease in molecular weight due to decomposition must be taken into account, but the latter is better selected for uniform mixing. The extrusion temperature needs to be appropriately adjusted depending on the mixing ratio of the aliphatic polycarbonate resin (A) and other resins, additives, etc., but is generally set in the range of 200 ° C to 260 ° C.

  Next, it is preferable that the sheet-like material melt-molded from the die at the tip of the extruder is brought into contact with a rotating casting drum (cooling drum) and rapidly cooled. The temperature of the casting drum needs to be appropriately adjusted depending on the mixing ratio of the aliphatic polycarbonate resin (A) and other resins and / or additives added as necessary, but it is in the range of 60 ° C to 130 ° C. Set to

  The film obtained by the above method has a glass transition temperature of the aliphatic polycarbonate resin (A) of usually −10 ° C. or higher and + 50 ° C. or lower, more preferably −5 ° C. or higher and + 40 ° C. or lower, more preferably the glass transition temperature. It is heated above the temperature and below + 30 ° C. and stretched in the length direction and the width direction. Here, the flow direction from the extruder of the film is referred to as the length direction, and the orthogonal direction is referred to as the width direction.

  In the film of the present invention, the unstretched film is 1.2 times or more in the width direction, preferably 1.3 times or more, more preferably 1.4 times or more, and 2.0 times or less, preferably 1. 9 times or less, more preferably 1.8 times or less, and 1.0 or more times in the length direction, preferably 1.02 times or more, 1.5 times or less, preferably 1.4 times or more. Hereinafter, those obtained by stretching in a range of 1.3 times or less are more preferable.

  As the stretching method, a roll stretching method in which a sheet is stretched between two rolls having a difference in peripheral speed, and / or a tenter that stretches a row of clip rows while holding the sheet with a clip using a tenter. The stretching method is most preferably employed industrially. After the stretching, the stretching strain is fixed so as to exhibit heat shrinkability by rapidly cooling by passing it through a low temperature zone of about 60 ° C. from room temperature.

<Method for producing heat-shrinkable tube>
The method for producing the heat-shrinkable tube of the present invention is not particularly limited, but usually a method of extruding an unstretched tube using a round die and then stretching the unstretched tube to obtain a heat-shrinkable tube. Is a preferred method. In addition, a method in which a film extruded / stretched using a T die or an I die is bonded by fusing, welding or bonding to form a tube, and further, the tube or film is bonded in a spiral to form a tube. Etc.

  Here, the method of extruding an unstretched tube using a round die and then stretching it into a heat-shrinkable tube will be described in more detail. Each raw material constituting the resin composition (X) is heated and melted to a temperature equal to or higher than the melting point by a melt extruder, continuously extruded from a round die, and then cooled to form an unstretched tube. As a cooling means, a method of immersing in low-temperature water, a method using cold air, or the like can be used. Of these, the method of immersing in low-temperature water is effective because of its high cooling efficiency. The unstretched tube may be continuously supplied to the next stretching step, or after being wound up into a roll, the unstretched roll may be used as a raw material for the next stretching step. From the viewpoint of production efficiency and thermal efficiency, a method of continuously supplying an unstretched tube to the next stretching step is preferable.

  Next, the unstretched tube formed by the above method is pressurized with compressed gas from the inside of the tube and stretched. The stretching method is not particularly limited, but, for example, it is sent out from one end of an unstretched tube at a constant speed while applying pressure by a compressed gas to the inside of the tube, and then heated by hot water or an infrared heater, etc. In order to regulate the draw ratio, drawing at a fixed ratio is performed through a cooled cylindrical tube. The temperature conditions and the like are adjusted so that the cylinder tube is stretched at an appropriate position. The stretched tube cooled by the cylindrical tube is sandwiched between a pair of nip rolls and taken up and wound as a stretched tube while maintaining the stretching pressure. Stretching may be performed in any order in the length direction or the radial direction, but is preferably performed simultaneously. Here, the flow direction from the extruder of a tube is called a length direction, and the orthogonal direction is called a radial direction.

  The stretching ratio in the length direction is determined by the ratio of the feed speed of the unstretched tube and the nip roll speed after stretching, and the stretching ratio in the radial direction is determined by the ratio of the unstretched outer diameter to the stretched tube outer diameter. As another stretching and pressurizing method, a method of maintaining the internal pressure of the compressed gas in which both the unstretched tube feed side and the stretched tube take-up side are sandwiched and sealed between nip rolls can be employed.

  The stretching conditions include the type of aliphatic polycarbonate resin (A), the blending ratio of the aliphatic polycarbonate resin (A), and other resins and / or additives added as necessary, and the purpose. Although it is adjusted by the heat shrinkage ratio, etc., the normal stretching temperature is usually from −10 ° C. to + 50 ° C., more preferably from −5 ° C. to + 40 ° C., more preferably from the glass transition temperature of the aliphatic polycarbonate resin (A). Is performed in the range of the glass transition temperature or higher and + 30 ° C. or lower.

  In the tube of the present invention, the unstretched tube is usually 1.2 times or more, preferably 1.3 times or more, more preferably 1.4 times or more, and usually 2.0 times or less, preferably 1 in the radial direction. 0.9 times or less, more preferably 1.8 times or less, and usually 1.0 times or more, preferably 1.02 times or more in the length direction, usually 1.5 times or less, preferably 1 It is preferably obtained by stretching in a range of 4 times or less, more preferably 1.3 times or less.

  If the draw ratio in the radial direction of the tube is less than 1.2 times, there may be a case where a sufficient amount of shrinkage cannot be obtained. On the other hand, when the draw ratio in the radial direction of the tube exceeds 3.0 times, the thickness fluctuation tends to increase. Moreover, when the draw ratio in the length direction of the tube exceeds 2.0 times, the contraction amount in the length direction becomes large, and the coating position may be shifted when an electronic component or the like is coated.

The heat-shrinkable film or tube has a heat shrinkage rate of 30% when left in a 100 ° C. silicone oil for 20 seconds, usually in the width direction of the film or in the radial direction of the tube.
The above is preferably 35%, more preferably 40% or more, and usually 70% or less, preferably 65% or less, more preferably 60% or less. In the film length direction or the tube length direction, it is 40% or less, preferably 15% or less, more preferably 5% or less, and most preferably 0%. If the heat shrinkage rate when left in a 100 ° C. silicone oil for 20 seconds is in the above range, it has excellent low temperature shrinkage properties, so that it can be used for food, medicine, cosmetics, paper or plastic containers that wrap them, or In addition, there is no risk of damaging the contents of capacitors, batteries, etc., and since it gradually shrinks from a low temperature, the coating finish in the process of coating the contents is improved and the coating speed is increased. It is expected.

  Furthermore, the heat-shrinkable molded article of the present invention is also excellent in UV discoloration resistance, and the color difference ΔE before and after xenon 72-hour irradiation is preferably 20 or less, more preferably 15 or less, and more preferably 10 or less. More preferably it is. If ΔE is 20 or less, it is not discolored even in outdoor use or in an environment irradiated with UV, and can maintain excellent transparency. The heat-shrinkable molded article of the invention can be used.

  The heat-shrinkable molded body of the present invention is mainly used in the form of a film or tube, for food, medicine, cosmetics, paper or plastic containers for wrapping them, or for covering capacitors such as aluminum electrolytic capacitors, electric wires (round Wire, square wire), secondary batteries such as dry batteries, lithium ion batteries, etc., steel tubes or motor coil ends, transformers and other electrical equipment and small motors, or fluorescent tubes covering tubes for light bulbs, fluorescent lamps, facsimiles and image scanners Is also available. Moreover, according to the use, shapes other than a film and a tube may be sufficient.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, the various measured values and evaluation displayed in this specification were performed as follows.

(1) Viscosity average molecular weight (Mv)
Using an Ubbelohde viscometer, a methylene chloride solution (0.6 g / dl) of a polycarbonate resin sample was prepared, and η _sp at 20 ° C. was measured. From the following formulas (I) and (II), the viscosity average molecular weight (Mv )
η _sp /C=[η]×(1+0.28η _sp) (I)
[Η] = 1.23 × 10 ⁻⁴ × (Mv) ^0.83 (II)
(In the formula (I), η _sp is the specific viscosity measured at 20 ° C. in methylene chloride of the polycarbonate resin sample, and C is the concentration of this methylene chloride solution. As the methylene chloride solution, the concentration of the polycarbonate resin sample is (Use a 0.6 g / dl solution.)

(2) Reduced viscosity
The reduced viscosity of the polycarbonate resin sample was measured at a temperature of 20.0 ° C. ± 0.1 ° C. using an Ubbelohde viscometer with a DT-504 automatic viscometer manufactured by Chuo Rika Co., Ltd., using methylene chloride as a solvent. The concentration was measured after being precisely adjusted to 0.60 g / dl.
From the passage time t _{0 of the} solvent and the passage time t of the solution, the following formula:
η _rel = t / t ₀
More seek relative viscosity eta _rel, from the relative viscosity eta _rel, the formula:
η _sp = (η−η ₀ ) / η ₀ = η _rel −1
The specific viscosity η _sp was determined.
By dividing the specific viscosity η _sp by the concentration c (g / dl), the following formula:
η _red = η _sp / c
From this, the reduced viscosity (converted viscosity) η _red was determined.
The higher this number, the greater the molecular weight.

(3) UV discoloration resistance Using a xenon weather meter WBL75XS made by Suga Test Instruments Co., Ltd., under conditions of surface illumination 60 W / cm ² , wavelength 300-400 nm, black panel temperature 63 ° C., relative humidity 50% For 72 hours. The color difference ΔE was measured for the samples before and after irradiation. A case where ΔE was 20 or less was regarded as acceptable.

(4) Total light transmittance, haze Based on JIS K7105, total light transmittance and diffuse transmittance were measured, and haze was calculated by the following formula. A sample having a total light transmittance of 80% or more and a haze of 3% or less at a thickness of 0.2 mm was regarded as acceptable.
[Haze] = [diffuse transmittance] / [total light transmittance] × 100
(5) Heat shrinkage rate 100 mm wide, 100 mm long film, or 30 mm diameter, 100 mm long tube after standing for 20 seconds in the width of the film, or tube diameter The direction shrinkage was calculated based on the following equation.
Heat shrinkage (%) = [(L0−L1) / L0] × 100
Here, L0 means a dimension before shrinkage, and L1 means a dimension after shrinkage.

(6) Impact resistance Using a hydroshot high-speed impact tester (“HTM-1 type” manufactured by Shimadzu Corporation), a sheet cut into a size of 900 mm in the length direction × 900 mm in the width direction or 900 mm in the radial direction is used as a sample. And fixing it with a clamp, dropping an impact core having a diameter of ½ inch in the center of the sheet at a temperature of 23 ° C. with a dropping speed of 3 m / sec, giving an impact, and the breaking energy (kgf · mm) when the sample breaks. It was measured. Those having a fracture energy of 100 kgf · mm or more were regarded as acceptable.

[Aliphatic polycarbonate resin (A)]
PC1:
Structural unit derived from isosorbide / Structural unit derived from 1,4-cyclohexanedimethanol = 30/70 mol%,
Glass transition temperature = 80 ° C., reduced viscosity 0.69 dl / g
PC2:
Structural unit derived from isosorbide / Structural unit derived from 1,4-cyclohexanedimethanol = 50/50 mol%,
Glass transition temperature = 101 ° C., reduced viscosity 0.57 dl / g
PC3:
Structural unit derived from isosorbide / Structural unit derived from 1,4-cyclohexanedimethanol = 60/40 mol%,
Glass transition temperature = 110 ° C., reduced viscosity 0.51 dl / g

[Aromatic polycarbonate resin (B)]
PC4:
Iupilon S3000 manufactured by Mitsubishi Engineering Plastics
Glass transition temperature = 150 ° C., viscosity average molecular weight = 20,000, reduced viscosity 0.49 dl / g

Example 1
PC1 is used as the aliphatic polycarbonate resin (A), melt kneaded at 220 ° C. using a 40 mmφ co-directional twin screw extruder, extruded from a T-die, and then rapidly cooled by a casting roll at about 70 ° C. Got. Next, the unstretched film was stretched 1.09 times in the length direction at a sheet temperature of 85 ° C. between two rolls with different peripheral speeds, and then the width was increased at 85 ° C. using a film tenter manufactured by Mitsubishi Heavy Industries. The film was stretched 2.0 times in the direction to obtain a heat-shrinkable film having a thickness of 0.1 mm. The obtained heat-shrinkable film was evaluated for UV discoloration resistance, total light transmittance, haze, heat shrinkage rate, and impact resistance. The results are shown in Table 1.

(Example 2)
A heat-shrinkable film was produced and evaluated in the same manner as in Example 1 except that PC2 was used as the aliphatic polycarbonate resin (A). The results are shown in Table 1.

(Example 3)
PC1 of the aliphatic polycarbonate resin (A) and PC4 of the aromatic polycarbonate resin (B) were blended at a mixing mass ratio of 80:20 to produce a heat-shrinkable film in the same manner as in Example 1, and And evaluated. The results are shown in Table 1.

(Example 4)
PC1 of the aliphatic polycarbonate resin (A) was melt-kneaded at 220 ° C. with a φ40 mm same-direction twin screw extruder, then extruded using a round die, immersed in water, cooled and solidified, and outer diameter 20 mm, thickness 0.2 mm. An unstretched tube was obtained. Next, the unstretched tube is heated with hot water at 85 ° C., stretched 1.09 times in the length direction and 1.8 times in the diameter direction, and then cooled to form a heat-shrinkable tube having an outer diameter of 11 mm and a thickness of 0.1 mm. Obtained. Table 1 shows the results of the same evaluation as in Example 1 for the obtained tube.

(Comparative Example 1)
A heat-shrinkable film was prepared and evaluated in the same manner as in Example 1 except that the aliphatic polycarbonate resin (A) was not used and PC4 of the aromatic polycarbonate resin (B) was used alone. The results are shown in Table 1.

(Comparative Example 2)
A heat-shrinkable film was produced and evaluated in the same manner as in Example 1 except that PC3 was used as the aliphatic polycarbonate resin (A). The results are shown in Table 1.

From Table 1, the heat-shrinkable molded article of the present invention was excellent in UV discoloration resistance, transparency, low-temperature shrinkage characteristics, and impact resistance as long as it was within the specified range of the present invention. On the other hand, in the comparative example, any of UV discoloration resistance, transparency, low temperature shrinkage characteristics, and impact resistance was inferior to the examples. This shows that the heat-shrinkable molded article of the present invention is a heat-shrinkable molded article excellent in UV discoloration resistance, transparency, low-temperature shrinkage characteristics, and impact resistance.

Claims (6)

A structural unit (a) derived from a dihydroxy compound represented by the following general formula (2) and a structural unit (b) derived from cyclohexanedimethanol,
A heat-shrinkable molded article comprising a resin composition (X) containing an aliphatic polycarbonate resin (A) having a proportion of the structural unit (b) of 45 mol% or more and 80 mol% or less. .

The resin composition (X) contains the aromatic polycarbonate resin (B) at a ratio of 1% by mass to 50% by mass with respect to 100% by mass of the aliphatic polycarbonate resin (A). The heat-shrinkable molded product according to claim 1 . The heat-shrinkable molded article according to claim 1 or 2 , wherein the heat-shrinkable molded article is a film or a tube. The heat-shrinkable molded article according to claim 3 , wherein the film has a heat shrinkage ratio in the width direction of 30% or more and 70% or less when left in a 100 ° C silicone oil for 20 seconds. . The heat-shrinkable molded article according to claim 3 , wherein the tube has a heat shrinkage ratio in the radial direction of 30% or more and 70% or less when left standing in 100 ° C silicone oil for 20 seconds. . Heat-shrinkable molded article according to any one of claims 1 to 5, the color difference ΔE before and after the xenon 72 hours irradiation of the heat-shrinkable molded article characterized in that it is 20 or less.