WO2004090026A1

WO2004090026A1 - Heat-shrinkable polyester tube and capacitor product covered therewith

Info

Publication number: WO2004090026A1
Application number: PCT/JP2004/005076
Authority: WO
Inventors: Yoshiyuki Hujitani; Kouichirou Taniguchi
Original assignee: Mitsubishi Plastics, Inc.
Priority date: 2003-04-09
Filing date: 2004-04-08
Publication date: 2004-10-21
Also published as: TW200502083A; JPWO2004090026A1

Abstract

A heat-shrinkable polyester tube which has excellent durability under high-temperature high-humidity conditions. The heat-shrinkable polyester tube is formed from a thermoplastic polyester resin composition comprising at least one hydrolysis inhibitor and a thermoplastic polyester resin. It is characterized in that when the tube which has been used for covering is allowed to stand for 30 hours under the conditions of a temperature of 130°C, relative humidity of 85%, and absolute vapor pressure of about 0.23 MPa in accordance with JIS C 0096 and then examined by gel permeation chromatography, then the polymer has a weight-average molecular weight Mw(30), in terms of polystyrene, of 30,000 to 150,000.

Description

Description Heat shrinkable polyester tubing and capacitor products coated with it

Technical field

The present invention relates to a heat-shrinkable polyester-based tube and use thereof, and more particularly, to endurance under high temperature and high humidity suitable for coating electronic components, particularly for coating a capacitor such as an aluminum electrolytic capacitor. The present invention relates to a heat-shrinkable polyester tube having excellent heat resistance and a capacitor product coated with the heat-shrinkable polyester tube.

Background art

Conventionally, heat-shrinkable tubes mainly made of polychlorinated vinyl have been widely used as electrical insulating materials used for capacitor coating applications. However, the heat-shrinkable tube made of polychlorinated vinyl has a problem that hydrogen chloride gas is generated at the time of combustion, and the incinerator is easily damaged during disposal treatment such as incineration. Therefore, heat shrinkable tubing made of polyester resin has come to be used as a substitute for polyvinyl chloride tubing from such an aspect. In recent years, electronic components such as capacitors have been increasing in density in order to reduce the weight and size of products, and heat resistance that can withstand heat generated by electronic components is required. For this reason, good heat resistance is also required for heat-shrinkable tubes made of polyester resin.

From such a background, a technology regarding a heat-shrinkable polyester tube having heat resistance is disclosed. For example, JP-A-2002-2642111 discloses that a thermoplastic polyester resin formed from a thermoplastic polyester resin having a specific composition has a crystallinity of 0.5% or more and less than 4%. Heat-shrinkable aromatic polyester Tubes have been proposed. In addition, Japanese Patent Application Laid-Open No. 3-224473 proposes a heat-shrinkable polyester tube having a crystallinity of 4 to 20%. In these publications, it is described that a heat-shrinkable polyester tube excellent in heat resistance, coating finish and the like can be obtained.

However, when used for coating aluminum electrolytic capacitors, the heat-shrinkable polyester tube described in the above-mentioned publication has not yet had sufficient durability under high temperature and high humidity. For example, electrical components of automobiles are often used inside a car under the sun or around an engine room, and are often required to have heat resistance. In addition, since it is directly affected by weather such as wind and rain, and dew condensation due to climate change, it is required to have appropriate heat resistance as well as heat resistance. If a capacitor covered with the above-mentioned heat-shrinkable polyester tube is left under high temperature and high humidity for a long time under such operating conditions, the tube gradually becomes brittle, and eventually cracks, breaks, and falls off the tube. However, problems have been pointed out, such as short-circuiting due to loss of the insulation properties of the capacitor, and inability to determine the polarity of the capacitor identified by printing on the tube surface. DISCLOSURE OF THE INVENTION ''

The present invention has been made to solve the above problems, and an object of the present invention is to provide a heat-shrinkable polyester tube having excellent durability under high temperature and high humidity, and a coating process with the heat-shrinkable polyester tube. To provide improved capacitor products.

As a result of intensive studies, the present inventors have found that a heat-shrinkable polyester tube having a specific composition can solve the above problems, and have completed the present invention.

That is, the heat-shrinkable polyester tube of the present invention is a heat-shrinkable tube formed from a thermoplastic polyester-based resin composition containing at least one type of hydrolysis inhibitor and a thermoplastic polyester-based resin. , Covering After that, according to JISC 0096, the tube was treated for 30 hours under the conditions of a temperature of 130 ° C, a relative humidity of 85%, and an absolute vapor pressure of 0.23 MPa. The obtained polystyrene-converted weight average molecular weight M w (30) is not less than 30,000 and not more than 150,000.

Here, the thermoplastic polyester resin composition may be a resin composition containing a polyethylene terephthalate resin as a main component.

In addition, the hydrolysis inhibitor may be a monomer or polymer of a carbodiimide compound.

The hydrolysis inhibitor may be contained in a ratio of 0.3 to 5.0 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin.

In the heat-shrinkable polyester tube according to the present invention, the hydrolysis inhibitor is a vinyl containing, as a constituent unit, a monomer unit having a functional group having a reactivity with at least one of a group consisting of a hydroxyl group and a hydroxyl group. It can be a polymer.

Here, the functional group may be an epoxy group.

In this case, the compounding amount of the hydrolysis inhibitor is in a range that satisfies the relationship of 97 to 80% by mass of the thermoplastic polyester resin and 3 to 20% by mass of the hydrolysis inhibitor. Is preferred. Meanwhile, the total of the thermoplastic polyester resin and the hydrolysis inhibitor is 100% by mass.

In the heat-shrinkable polyester tube of the present invention, it is preferable that the molecular weight retention of the heat-shrinkable polyester tube formed from the thermoplastic polyester resin composition satisfies the following expression. Molecular weight retention = Mw (30) / Mw (0) ≥ 0.4

(Where Mw (0) is the gel permeation of the heat-shrinkable polyester tube. Mw (30) is the initial weight-average molecular weight in terms of polystyrene determined by the application chromatography, and the temperature is 130 ° C according to JISCO096 after coating the heat-shrinkable tube. Polystyrene determined by gel permeation chromatography of heat-shrinkable polyester tubes after 30 hours of treatment under conditions of relative humidity of 85% and absolute vapor pressure of 0.23 Mpa It is a converted weight average molecular weight. Also, when the heat-shrinkable polyester tube is immersed in warm water of 98 ± 2 ° C for 30 seconds, the heat shrinkage ratio is 30 to 70% in the radial direction and 0 to 70% in the length direction. It can be 40%.

The capacitor product of the present invention is characterized by being coated with any one of the heat-shrinkable polyester-based tubes described above. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

The heat-shrinkable polyester tube of the present invention is a heat-shrinkable tube formed from a thermoplastic polyester-based resin composition containing at least one type of hydrolysis inhibitor. '

Here, the thermoplastic polyester resin composition is a resin composition containing at least one kind of thermoplastic polyester resin as a main component. The thermoplastic polyester resin comprises a dicarboxylic acid component and a diol component.

Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, 2-chloroterephthalenoic acid, 2,5-dichloroterephthalanoic acid, 2-methinoleterephthalic acid, 4,4-stilbenedicarboxylic acid, 4,4 1-Bibundyl dicarboxylic acid, onoletophthalanoic acid, 2,6-naphthalenedicanoleponic acid, 2,7-naphthalenedicarboxylic acid, bisbenzoic acid, bis (p-potoxyphenyl) methane, anthracenedicarboxylic acid, 4 , 4 diphenyl ether dicarboxylic acid, Aromatic dicarboxylic acids such as 4,4-diphenoxyethane dicarboxylic acid, 5-Na sulfoisophthalic acid, ethylene-bis-p-benzoic acid, adipic acid, sebacic acid, azeline acid, dodecane diacid, 1, Examples include aliphatic dicarboxylic acid components such as 3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid. One of these dicarboxylic acid components may be used alone, or two or more thereof may be used in combination.

Examples of the diol component include diethylene glycol, ethylene glycol cornole, 1,2-propylene glycol cornole, 1,3-propanedioleone, 2,2-dimethyl-1,3-propanediol, trans-tetramethyl-1,4 3-cyclobutanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 1,4-butanediol, neopentynole glycol, 1,5-pentanediol, 1,6-hexanediol, 1 , 4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, decamethylene glycol cornole, hexagonal hexane, p-xylene diamine, bisphenol A, tetrabromobisphenol A, tetra Bromobisphenol A monobis (2-hydroxyshethyl ether) etc. And the like. These diol components may be used alone or as a mixture of two or more.

Examples of the thermoplastic polyester resin comprising a dicarboxylic acid component and a diol component include polyethylene terephthalate resin, polypropylene terephthalate resin, polybutylene terephthalate resin, polyethylene isophthalate resin, polyethylene naphthalate resin, polybutylene naphthalate resin, Examples include polyethylene terephthalate / isophthalate copolymer resin, polyethylene z neopentyl terephthalate copolymer resin, and the like. In addition, a high melting point and high crystalline aromatic polyester as a hard segment and a thermoplastic polyester elastomer composed of an amorphous polyester or an amorphous polyether as a soft segment may be appropriately mixed. They are, One type may be used alone, or two or more types may be used in combination.

In the present invention, as the thermoplastic polyester resin, a resin composition containing a polyethylene terephthalate resin as a main component or a resin obtained by mixing a small amount (about 1 to 15% by mass) of a polyethylene terephthalate resin with a polyethylene terephthalate resin The composition is preferably used. Here, polyethylene terephthalate resin (hereinafter sometimes abbreviated as PET resin) is a resin polymerized mainly using terephthalic acid as a dicarboxylic acid component and ethylene glycol as a diol component. A quantity (10 mol% or less) of a copolysynthetic component may be contained. For example, the PET resin contains about 0.5 to 5.0 mol% of an isophthalic acid component and a diethylene glycol component (including by-product components).

The method for producing the thermoplastic polyester resin used in the present invention may be a conventional method using a compound of antimony (S b), germanium (G e) ゝ titanium (T i), or aluminum (A 1). The reaction is carried out by polymerizing the dicarboxylic acid component and the diol component while heating in the presence of the contained polycondensation catalyst, and discharging water or lower alcohol produced as a byproduct to the outside of the system.

Here, examples of the antimony (Sb) compound include antimony trioxide, antimony acetate, antimony tartrate, antimony potassium tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, trifenylantimony and the like.

As the germanium (Ge) compound, amorphous germanium dioxide, crystalline germanium dioxide powder or a slurry of ethylene glycol, a solution prepared by heating and dissolving crystalline germanium dioxide in water, or ethylene glycol added thereto A heat-treated solution or the like is used.

Titanium (T i) compounds include tetraethyl titanate, tetraisopropyl pyrititanate, tetra-n-propyl titanate, tetra-n-butyl Tetraalkyl titanates such as titanates and their partial hydrolysates, titanyl oxalate, titanyl ammonium oxalate, titanyl sodium oxalate, potassium titanyl oxalate, titanyl oxalate compounds such as titanyl calcium oxalate, titanyl strontium oxalate, and trimellitium Titanium tomate, titanium sulfate, titanium chloride and the like.

Aluminum (A 1) compounds include carboxylate salts such as aluminum formate, aluminum acetate, aluminum propionate, and aluminum oxalate; and oxides, inorganic hydroxides such as aluminum hydroxide, aluminum chloride, aluminum hydroxide chloride, and aluminum carbonate. Aluminum alkoxides, such as acid salts, aluminum methoxide, aluminum ethoxide, etc., aluminum chelates with aluminum acetyl acetonate, aluminum acetyl acetate, etc., and organic aluminum, such as trimethyl aluminum and triethyl aluminum Dimethyl compounds and their partially hydrolyzed products.

In the case of the A1 compound, an alkaline metal compound or an alkaline earth metal compound may be used in combination. Examples of the alkali metal compound or alkaline earth metal compound include carboxylate salts such as acetates of these elements, alkoxides and the like, and are added to the reaction system as powder, aqueous solution, ethylene glycol solution and the like.

In the present invention, the polymerization catalyst used for producing the thermoplastic polyester resin is not particularly limited. In the present invention, compounds such as manganese, zinc, calcium, and magnesium, which are used in a transesterification reaction which is a stage prior to conventionally known polycondensation, can be used in combination. Further, after the transesterification reaction, it is also possible to deactivate such a catalyst with a phosphoric acid compound, a phosphorous acid compound or the like to carry out polycondensation.

As a method for producing a thermoplastic polyester resin, any of a batch method and a continuous polymerization method can be used. In addition, it is also possible to employ any of a solution polymerization method and a solid phase polymerization method.

Using tetrachloroethane Z phenol (mass ratio 1/1) as a solvent at 30 ° C The measured intrinsic viscosity of the thermoplastic polyester resin is in the range of 0.4 to 1.5 d1 g, preferably in the range of 0.7 to 1.2 dlZg. Here, if the intrinsic viscosity is less than 0.4 d 1 / g, the moisture resistance, mechanical properties, breaking strength and elongation of the tube will be low, while if it exceeds 1.5 d 1 / g, the melt processability of the tube will be low. And the polymerization takes a long time, which is not preferable in terms of production cycle and cost.

Next, the hydrolysis inhibitor will be described. It is important that the above-mentioned thermoplastic polyester-based resin composition used for producing the heat-shrinkable polyester-based tube of the present invention contains at least one type of hydrolysis inhibitor. Since the hydrolysis inhibitor has a function of suppressing the hydrolysis of the ester bond of the polyester, the effect of moisture and moisture during the melting and kneading process of the tube and in the actual use environment of the tube is considered. This can prevent the polyester from deteriorating.

Examples of the hydrolysis inhibitor include a monomer or polymer of a funinol compound, a carbodiimide compound and a monomer or polymer of an oxazoline compound, or a reactivity with a carboxyl group and / or a hydroxyl group. And a butyl polymer containing a monomer unit having a functional group having the following as a component (hereinafter, also referred to as a “reactivity modifier”). In the present invention, a monomer or polymer of a carbodiimide compound or a reactivity modifier is most preferably used. Here, specific examples of the phenolic compound include hindered phenol, thiobisphenolone, anoreclidenebisphenol, anorecquinolephenolene, hydridoxybenzil compound, and acrylylaminophenol. And hydroxyphenylpropionate. Particularly preferred are esters of 3,5-di-tert-butyl-41-hydroxyphenylpropionic acid with pentaerythritol and 1-octadecanonole, and Irganox (registered trademark, Ciba Specialty). Chemicals). Specific examples of the above compounds are described in “Kunststof f addit ivej (plastic additive)” by Gachter and Muller. 2nd edition (Carl Hanser Verlag).

The phenolic compound is preferably used in combination with an organic phosphorus compound. As the organic phosphorus compound, triallyl phosphite is preferable, and it is available as Irgafos 168 (registered trademark, manufactured by Ciba Specialty Chemicals). Since the organic phosphorus compound has a function of decomposing peroxide, it can be said to be a second stabilizer. A mixture of a phenolic compound and an organic phosphorus compound is also commercially available as Irganox B 561, Irganox B 225 (registered trademark).

Further, examples of the calposimid compound used in the present invention include those having a basic structure represented by the following general formula (1).

-(N = C-N-R-) n-(1) In the formula, n is an integer of 1 or more, and R represents an organic bonding unit. For example, R can be aliphatic, cycloaliphatic, or aromatic. Further, n is usually selected from a suitable integer between 1 and 50. When n is an integer of 2 or more, two or more Rs may be the same or different.

Specific examples include bis (propylphenyl) carbodiimide, bis (diphenylpyrufenolinole) caspositoimid, poly (4,4, -diphenylmethane phenol), poly (p-phenylene carbodiimide), Poly (m-phenylene carbodiimide), Poly (tolyl carbodiimide), Poly (diisopropinole phenylene propylene), Poly (methylinopropyl isopropylenephenylene propylene), Poly (triisopropyl phenyl) Lencarposimid), aromatic polycarposimid, etc., and these monomers are exemplified as carposimid compounds. These carbodiimide compounds may be used alone or in combination of two or more. As the polymer of the carbodiimide compound, those having a molecular weight of 2,000 to 500,000 are preferable. Specifically, Stabaxol p and Stabaxol P100 (registered trademark, Rhein Chemie GmbH) Mannheim), Carpositoite HMV 8CA (registered trademark, manufactured by Nisshinbo Industries, Inc.) and the like.

When a monomer or polymer of a phenolic compound or a carbodiimide compound or a monomer or polymer of an oxazoline compound is used as the hydrolysis inhibitor, the amount of the hydrolysis inhibitor is The amount is preferably from 0.3 to 5.0 parts by mass, more preferably from 0.5 to 5.0 parts by mass, particularly preferably from 0. 0 to 5.0 parts by mass, based on 100 parts by mass of the thermoplastic polyester resin used. It is 75 to 3.0 parts by mass. Here, if the amount of the hydrolysis inhibitor is less than 0.3 parts by mass, the effect of the hydrolysis inhibitor may not be remarkable, while if it exceeds 5.0 parts by mass, the hydrolysis prevention The effect as an agent is saturated, the melt viscosity at the time of extrusion becomes too high, and the moldability tends to deteriorate, and the cost tends to increase, which is not preferable.

As described above, in the present invention, as a hydrolysis inhibitor, a butyl polymer containing a monomer unit having a functional group reactive with a carboxy group and / or a hydroxyl group as a constituent unit (reactive modification) May be used. Hereinafter, the reactivity modifier will be described.

Examples of the monomer having a functional group having reactivity with a carboxyl group or a hydroxyl group include an acid anhydride group, an epoxy group, an oxazoline group, and the like. In the case of a monomer having a _c- epoxy group, it is preferable to use a polymer, which can appropriately facilitate the reaction with a carboxyl group and reduce the molecular weight due to hydrolysis during extrusion melting of a thermoplastic polyester resin. This is preferable because the effect of improving the molecular weight by, for example, increasing the chain length is exhibited. Specific examples of the monomer having an epoxy group include glycidyl methacrylate, glycidyl acrylate, (3,4-epoxycyclyl hexyl) methyl methacrylate, and the like.

The amount of the monomer unit having a functional group reactive with a carboxyl group and / or a hydroxyl group is preferably in the range of 5 to 95% by mass of the reactivity modifier. Reactive reforming The agent may contain, as a component, a monomer unit other than a monomer unit having a functional group reactive with a carboxyl group and / or a hydroxyl group. Specific examples of other monomer units include monomers having an aromatic ring such as styrene and _α -methylstyrene, and methyl acrylate, methyl acrylate, propyl acrylate, butyl acrylate, and 2-ethyl hexyl acrylate. Hexinoleate tallate, methinolemethacrylate, ethynolemethacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate and the like.

The reactive modifier is produced by polymerizing a monomer having a functional group having reactivity with a carboxyl group and / or a hydroxyl group, and if necessary, other monomers with a known method. You. Preferable production methods of the reactive modifier include JP-A-57-502, JP-A-59-62071, and JP-A-60-21. A method by high-temperature continuous polymerization disclosed in Japanese Patent Application Laid-Open No. 507/07 is cited. That is, a method in which the mixture of the above monomers is continuously supplied at a constant supply rate into a reactor set to a predetermined temperature and pressure, and an amount of the reaction liquid corresponding to the supplied amount is extracted. Specific examples of the reactive modifier are commercially available from Toagosei Co., Ltd. under the trade name "ARUFONG" series and the trade name "XG" series.

When a reactive modifier is used as the hydrolysis inhibitor, the reactive modifier is used in an amount of 97 to 80% by mass of the thermoplastic polyester resin and 3% by mass of the reactive modifier. It is preferable that the content of the reactive modifier is 5 to 15% by mass based on 95 to 85% by mass of the thermoplastic polyester resin. Here, if the content of the reactive modifier is less than 3% by mass, it is difficult to sufficiently exhibit durability under high temperature and high humidity. In addition, due to hydrolysis during extrusion melting of the thermoplastic polyester resin. The effect of suppressing the decrease in the molecular weight is small, and the effect of improving the molecular weight by elongation of the chain is small. Therefore, it is difficult to make the molecular weight retention rate, M w (30) / M w (0), described later, 0.4 or more. It is not preferable because it easily becomes. On the other hand, when the amount of the reactive modifier exceeds 20% by mass, heat resistance generally tends to decrease, which is not preferable.

In the present invention, a chain extender, a crosslinking agent, and the like, for example, a diisocyanate compound, an epoxy compound, an acid anhydride, and the like may be used in combination for the purpose of increasing the initial molecular weight.

The heat-shrinkable polyester tube of the present invention may have a weight-average molecular weight Mw (30) of not less than 30,000 and not more than 150,000 after coating and high-temperature and high-humidity treatment. is necessary. Here, the coated heat-shrinkable polyester tube was used under the conditions of a temperature of 130 ° C, a relative humidity of 85%, and an absolute vapor pressure of about 0.23 MPa according to JISC 096. After performing the treatment for 30 hours, the weight average molecular weight Mw (30) in terms of polystyrene is determined by gel permeation chromatography measurement.

In the present invention, if the weight average molecular weight Mw (30) is less than 30,000, it becomes extremely brittle in a use environment under high temperature and high humidity, and cracks, cracks, falling off, etc. of the tube are likely to occur, which is not preferable. . On the other hand, if the weight-average molecular weight Mw (30) exceeds 150,000, the initial molecular weight is too high, so that the moldability of the tube during extrusion processing tends to be poor, which is not preferable. From these facts, a preferable range of the weight average molecular weight Mw (30) is 35,000 or more, 130,000 or less, and particularly preferably 40,000 or more, 120,000 or more. 000 or less.

The heat-shrinkable polyester tube of the present invention preferably has a molecular weight retention of 0.4 or more, that is, Mw (30) / Mw (0) ≥ 0.4. Here, .Mw (0) is the weight average molecular weight of the heat-shrinkable polyester tube before the heat treatment. That is, for the heat-shrinkable polyester tube before heat shrinkage, the weight average molecular weight Mw (0) in terms of polystyrene is determined by gel permeation chromatography measurement. When the molecular weight before the heat shrinkage is maintained after the heat shrinkage, the molecular weight retention rate becomes the upper limit of 1.0. When the molecular weight retention rate is less than 0.4, that is, when Mw (30) / Mw (0) <0.4, the effect of the molecular weight retention by the hydrolysis inhibitor or the like is insufficient, and it is very brittle under high temperature and high humidity. This is not preferable because the tube tends to be cracked, cracked, and dropped off. The Mw (30) Since the / M w (0) suitable range of values of 0.5 or more, _c but particularly preferably 0.6 or more, and the upper limit value is a 1.0, as described above .

In the present invention, in order to set Mw (30) / Mw (0) to 0.4 or more, the raw materials are sufficiently dried before the tube is manufactured, and the water content is 0.1% by mass or less, preferably 0.05% by mass or less, simultaneous use of vacuum vent extrusion with a co-axial twin screw extruder, etc., or together with these, the vinyl polymer according to the present invention is defined in the present invention as a thermoplastic polyester resin. It is preferable to mix them in proportions.

Next, a method for producing the heat-shrinkable tube of the present invention will be described. The production method is not particularly limited, but a preferred method is to extrude an unstretched tube using a round die and then stretch it to form a seamless heat-shrinkable tube. In addition, a method in which a film extruded and stretched using a T-die or a 1-die is bonded into a tube shape by fusing, welding, or bonding, and a tube shape is formed by bonding the above tube or film in a spiral shape. And the like.

Here, the method of extruding an unstretched tube using a round die and then stretching to form a heat-shrinkable tube will be described in further detail. The thermoplastic polyester resin composition described above 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, then forcibly cooled and molded into an undrawn tube. As a means for forced cooling, a method of immersion in low-temperature water, a method using cold air, and the like can be used. Above all, the method of immersion in low-temperature water is effective because the cooling efficiency is high. This unstretched tube may be continuously supplied to the next stretching step, or the unstretched tube may be once wound into a roll and then unrolled. The stretching roll may be used as a raw material for the subsequent stretching step. From the viewpoint of production efficiency and thermal efficiency, it is preferable to continuously supply the undrawn tube to the next drawing step.

The unstretched tube thus obtained is stretched by pressurizing the inside of the tube with a compressed gas. The stretching method is not particularly limited.For example, pressure is applied from one end of the unstretched tube to the inside of the tube while applying a pressure of compressed gas to the tube at a constant speed, and then heated with hot water or an infrared heater, etc. In order to regulate the stretching ratio in the direction, stretch at a fixed ratio through a cooled cylindrical tube. The temperature conditions and the like are adjusted so that stretching is performed at an appropriate position in the cylindrical tube. The stretched tube cooled by the cylindrical tube is taken up and wound up as a stretched tube while holding the stretching pressure between the pair of nip rolls. Stretching may be performed in either the longitudinal direction or the radial direction, but is preferably performed simultaneously. The stretching ratio in the length direction is determined by the ratio between the feeding speed of the unstretched tube and the nipple 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 pressurizing method, a method in which both the unstretched tube feeding side and the stretched tube take-up side are sandwiched by nip rolls to maintain the internal pressure of the sealed compressed gas can be adopted.

The stretching conditions are adjusted according to the properties of the thermoplastic polyester resin composition to be used, the intended heat shrinkage, and the like. It is performed within the range of 100 ° C to 100 ° C.

In the heat-shrinkable polyester tube of the present invention, the unstretched tube is 1.2 to 3.0 times, preferably 1.3 to 2.5 times, more preferably 1.4 to 2.0 times in the diameter direction. It is preferable to stretch the film twice. Further, it is preferably obtained by stretching the film in a length direction of 1.0 to 2.0 times, preferably 1.02 to 1.5 times, more preferably 1.02 to 1.3 times. If the stretching ratio in the radial direction of the tube is less than 1.2 times, sufficient shrinkage cannot be obtained for coating. On the other hand, if it exceeds 3 times, the thickness fluctuation tends to increase, and the shrinkage tends to decrease due to directional crystallization, which is not preferable. If the stretching ratio in the length direction of the tube exceeds 2.0 times, the amount of shrinkage in the length direction increases, and the coating position shifts when coating electronic components, etc., or the cut length becomes longer. This is not preferable because it leads to higher costs.

From these facts, the heat-shrinkable polyester tube of the present invention has a heat shrinkage of 30 to 70% in the radial direction of the tube when immersed in warm water of 98 soil 2 ° C for 30 seconds. Is more preferable, and more preferably 35 to 50%. It is preferably 0 to 40%, more preferably 1 to 15%, in the length direction of the tube.

The thickness of the tube obtained as described above is not particularly limited. However, the thickness of the tube generally used for a capacitor is approximately 0.05 mm, depending on the rated voltage of the capacitor. 11.0 mm, typically 0.07 mm to 0.2 mm.

The thermoplastic polyester-based resin composition used in the heat-shrinkable polyester-based tube of the present invention is prepared by mixing the respective components in advance using a mixer such as a tumbler, a V-type blender, a pan parry mixer, a kneading roll, and an extruder. may be supplied to each component directly with pre-weighed into the feed throat of an extruder for extruding which may _c Alternatively unstretched tube, and the respective supply port of the extruder with two points or more supply ports The weighed components may be supplied separately. Further, in the present invention, a known method can be used as a method for mixing various additives described below including the hydrolysis inhibitor. For example, (a) separately prepare a master patch in which various additives are mixed with a suitable base resin such as polyethylene terephthalate resin at a high concentration (typically, about 5 to 60% by mass), A method of adjusting the concentration to the resin to be used and mixing it, (b) a method of directly mixing various additives with the resin to be used, and the like can be mentioned. The thermoplastic polyester resin composition of the present invention contains a polyolefin resin, a polyamide resin, and the like for the purpose of improving and adjusting the moldability and physical properties of the tube within a range that does not significantly impair the effects of the present invention. Non-polyester resins such as polycarbonate resins, flame retardants, weathering stabilizers, heat stabilizers, antistatic agents, antiblocking agents, melt viscosity improvers, crosslinkers, lubricants, nucleating agents, plasticizers, antiaging Additives such as a chemical, a hydrochloric acid absorbent, an antioxidant, another hydrolysis inhibitor, a coloring agent, and a pigment may be appropriately added.

The thermoplastic polyester resin composition used in the present invention has a water content of 0.1% by mass or less, preferably 0.05% by mass or less in advance in order to avoid hydrolysis of the polyester resin in the extruder. It is preferable to dry it sufficiently. For example, drying is performed at 170 ° C. for 3 hours, at 150 ° C. for 12 hours, and under vacuum conditions at 120 ° C. for 24 hours. Further, a method of performing so-called non-drying extrusion in which a vacuum vent is performed using a co-directional twin-screw extruder is also cited as a preferred method. As described above, the heat-shrinkable polyester tube of the present invention can be suitably used for coating a capacitor such as an aluminum electrolytic capacitor. However, for other uses, for example, electric wires (round wire, square wire) ), Dry batteries, rechargeable batteries such as lithium-ion batteries, electric equipment such as steel tubes or motor coil ends, transformers and small motors, or tubes for covering fluorescent lamps such as light bulbs, fluorescent lamps, fax machines, and image scanners. Is also available. Example

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In addition, various measured values and evaluations of the tube displayed in this specification were performed as follows. In the present invention, the flow direction of the tube from the extruder is referred to as “length direction”, and the direction perpendicular thereto is referred to as “radial direction”. (1) Heat shrinkage

After immersion in warm water of 98 ± 2 ° C for 30 seconds, the heat shrinkage in each of the length direction and the radial direction was calculated based on the following equation. Heat shrinkage (%) = [(L0-L1) / L0] XI00 In the formula, L0 is a dimension before shrinkage, and L1 is a dimension after shrinkage.

(2) Finish of coating

Using a hot air circulation type shrink tunnel (manufactured by Kyowa Denki Co., Ltd.), shrink the heat-shrinkable tube at 10 ° C for 20 seconds using 10 hot-air circulating shrink tunnels. Coating was performed. Thus, 10 capacitors covered with the heat-shrinkable tube were produced. After that, heat treatment was performed in a hot-air circulating thermostat for 85 to 90 minutes, and then left at room temperature for 2 hours. The condition of the tube after standing was evaluated based on the following criteria. Evaluation criteria:

(〇) There is no gap between the condenser and the heat-shrinkable tube, and no rise is observed at the end of the heat-shrinkable tube.

(X) There was a gap between the condenser and the heat-shrinkable tube, or at least one heat-shrinkable tube had a rising edge.

(3) Weight average molecular weight Mw (0)

The heat-shrinkable tube at the initial stage (before heat-shrinkage) was used as a sample, and HLC-8120 GPC manufactured by Tosoh Corporation was used as a measuring machine. The solution concentration was adjusted by dissolving 25 mg of the sample with 0.25 ml of hexafluoroisopropanol and further adding 5 ml of chloroform. Also, the column Using two KD-80M and KD-803 (manufactured by Showa Denko KK) connected in series, the solution injection amount is 10 μl, the solvent flow rate is 1. Oml / min, and the solvent temperature is Was measured at 40 ° C., and the weight-average molecular weight was calculated in terms of polystyrene (an average value of 10 samples was calculated, and fractions less than 100 were rounded down). The weight average molecular weight of the standard polystyrene used is 2,000, 000, 670,000, 110,000, 35,000, 10, 000, 4, 000, 600.

(4) High temperature and high humidity resistance

Using a hot-air circulation type shrink tunnel (manufactured by Kyowa Electric Co., Ltd.), 10 aluminum electrolytic capacitors with an outer diameter of 10 mm are shrink-coated with heat shrinkable tubes at 220 ° C for 10 seconds. After performing the process, it was left in a constant temperature bath at 85 ° C for 90 minutes, and further left at room temperature for 2 hours. After that, the aluminum electrolytic capacitor was subjected to a temperature of 130 ° C, relative to JISCO096 using a super-accelerated life tester (PC-422R7 type) manufactured by Hirayama Manufacturing Co., Ltd. The humidity was set at 85%, the absolute vapor pressure was set at about 0.23 MPa, the test was performed for 30 hours, and then the apparatus was allowed to stand until it reached room temperature. After the test, the appearance of the heat-shrinkable tube was visually observed and evaluated based on the following criteria. Evaluation criteria:

(〇) No heat-shrinkable tube with cracks, cracks, shedding, etc. (X) One or more heat-shrinkable tubes with cracks, cracks, shedding, etc.

(5) Weight average molecular weight Mw (30)

After completing the above evaluation of “(4) Resistance to high temperature and high humidity”, the heat-shrinkable tube was peeled off from 10 aluminum electrolytic capacitors. The weight average molecular weight of this heat-shrinkable tube was determined in the same manner as in “(3) Weight average molecular weight Mw (0) J”. (6) Comprehensive evaluation

Regarding the obtained results, “評価” indicates that all evaluations were good and there was no practical problem, and “X” indicates that any one of them was defective. (Example 1)

As shown in Table 1, fully dried polyethylene terephthalate resin (dicarboxylic acid component of terephthalic acid: 100 moles ^_0/0, the diol component Echire Nguri calls: 96.7 mol%, diethylene glycidyl Konore: 3.3 mole %, Polymerization catalyst: antimony, intrinsic viscosity: 1. O dl / g, weight average molecular weight Mw: 104,000 measured on raw pellets (hereinafter referred to as “PET resin II”) 100 parts by mass, 1 part by mass of Stabaxol P100 (manufactured by Line Chemie Japan KK) as a hydrolysis inhibitor, and 0.15 parts by mass of silica as a lubricant A resin composition was used. This thermoplastic resin composition was melt-mixed at a cylinder temperature of 270 ° C. using a 37 mm co-rotating twin screw extruder (LD = 28), and extruded using a round die. Then, it was immersed in water and cooled and solidified to prepare an unstretched tube. The obtained unstretched tube was subsequently heated with hot water at 90 ° C, stretched 1.08 times in the length direction and 1.85 times in the radial direction, and then cooled to obtain an outer diameter of 10.9 times. A heat-shrinkable polyester tube having a diameter of 0.1 mm and a thickness of 0.10 mm was obtained. The above measurement and evaluation were performed on the obtained heat shrinkable tube. Table 1 shows their characteristics.

(Example 2)

As shown in Table 1, in Example 1, 95 parts by mass of the same PET resin was used instead of 100 parts by mass of the PET resin, and a sufficiently dried polybutylene terephthalate resin (the dicarboxylic acid component was terephthalic acid). : 100 mol%, diol component is 1,4-butanediol: 100 mol%, melting point: 225 ° C, weight Cocatalyst: titanium-based, intrinsic viscosity: 0.9 d 1 / g, weight average molecular weight M w: 64, 800 measured from raw pellets (hereinafter referred to as “PBT resin”) 5 A heat-shrinkable polyester tube was produced in the same manner as in Example 1 except that the drawing ratio in the radial direction was changed to 1.75 times by mass. The measurement and evaluation described above were performed on the obtained heat-shrinkable tube. Table 1 shows the characteristics.

(Example 3)

As shown in Table 1, a heat-shrinkable polyester tube was obtained in the same manner as in Example 2, except that the addition amount of the hydrolysis inhibitor was changed to 5 parts by mass. The measurement and evaluation described above were performed on the obtained heat-shrinkable tube. Table 1 shows its characteristics.

(Comparative Example 1)

As shown in Table 1, a heat-shrinkable tube was obtained in the same manner as in Example 1 except that no hydrolysis inhibitor was added. The measurement and evaluation described above were performed on the obtained heat-shrinkable tube. _C to the characteristics shown in Table 1

(Comparative Example 2)

As shown in Table 1, a heat-shrinkable tube was obtained in the same manner as in Example 2, except that the addition amount of the hydrolysis inhibitor was changed to 0.2 parts by mass. The above measurement and evaluation were performed on the obtained heat-shrinkable tube. Table 1 shows the characteristics. Mw (30) was 27,500. table 1

As is clear from Table 1, as in Examples 1 to 3, it was confirmed that the heat-shrinkable polyester tube having a specific composition had excellent durability under high temperature and high humidity. On the other hand, Comparative Example 1 in which no hydrolysis inhibitor was added and Comparative Example 2 in which M w (30) was less than 30,000 had insufficient durability under high temperature and high humidity. It was confirmed that.

(Example 4)

As shown in Table 2, fully dried polyethylene terephthalate resin (Jikarupon acid component terephthalic acid 1 0 0 mole ^_0/0, the diol component include ethylene glycol 9 9.5 mol%, diethylene glycol 0.5 mol%, the melting point : 253 ° C, polymerization catalyst: antimony, intrinsic viscosity: 1.0 d 1 / g) (hereinafter referred to as PET resin II) (92 parts by mass) and Toa Gosei Chemical Co., Ltd. as a hydrolysis inhibitor ARUFON XG—401 0 (Catalog value: M = 2,900, Tg = _57 ° C, Epoxy value: 1.4 meq / g, Properties: Liquid, butyl acrylate-glycidyl acrylate) A thermoplastic polyester-based resin composition comprising 8 parts by mass of a polymer) (hereinafter referred to as “reactivity modifier II”) and 0.15 parts by mass of silica as a lubricant was used. This thermoplastic polyester resin composition was melt-mixed at a cylinder temperature of 270 ° C. using a 37 mm φ co-directional twin screw extruder (L / D = 28), and extruded using a round die. Next, it was immersed in water and cooled and solidified to prepare an unstretched tube. The obtained unstretched tube is continuously heated with hot water at 90 ° C, stretched 1/10 times in the length direction and 1.9 times in the radial direction, and then cooled to obtain an outer diameter of 10. A heat-shrinkable polyester tube having a diameter of 9 mm and a thickness of 0.10 mm was obtained. The above measurement and evaluation were performed on the obtained heat-shrinkable polyester tube. Table 2 shows the characteristics.

(Example 5)

As shown in Table 2, heat shrinkage was performed in the same manner as in Example 4 except that the mixing amount of the PET resin ② and the reactive modifier ① was changed to 97 parts by mass / 3 parts by mass. A polyester-based tube was obtained. The same measurement and evaluation as in Example 4 were performed on the obtained heat-shrinkable polyester tube. Table 2 shows their characteristics.

(Comparative Example 3)

As shown in Table 2, a heat-shrinkable tube was prepared in the same manner as in Example 4 except that the mixing amount of the PET resin ② and the reactive modifier に was changed to 100 parts by mass / 0 parts by mass. I got one. About the obtained heat-shrinkable polyester-based tube, The same measurement and evaluation as in Example 4 were performed. The characteristics shown in Table 2 _(Table 2

As is clear from Table 2, as in Examples 4 and 5, a thermoplastic polyester tube containing a PET resin and a reactive modifying agent (hydrolysis inhibitor) and having a specific molecular weight characteristic has a high temperature. The durability under high humidity was confirmed to be excellent. On the other hand, in Comparative Example 4, which did not contain the reactivity modifier, it was confirmed that the durability under high temperature and high humidity was insufficient. According to the present invention, it is possible to provide a heat-shrinkable polyester tube excellent in durability under high temperature and high humidity and a capacitor product covered with the heat-shrinkable polyester tube. Industrial applicability

The heat-shrinkable polyester tube of the present invention can be suitably used for coating electronic components and the like, particularly for coating capacitors such as aluminum electrolytic capacitors. However, other uses such as electric wires (round wire, square wire, etc.) can be used. Batteries, dry batteries, rechargeable batteries such as lithium-ion batteries, electric equipment such as copper tubes or motor coilends, transformers and small motors, or tubes for covering light bulbs, fluorescent lamps, facsimile and image scanner fluorescent lamps. Is also available.

Claims

The scope of the claims

1. A heat-shrinkable tube formed from a thermoplastic polyester resin composition containing at least one type of hydrolysis inhibitor and a thermoplastic polyester resin, which conforms to JISC 096 after coating. Temperature of 130 ° C, relative humidity of 85%, absolute vapor pressure of 0.23 MPa, and then processed by gel permeation chromatography using a tube treated for 30 hours. The heat-shrinkable polyester tube having a polystyrene-equivalent weight average molecular weight M w (30) of not less than 30,000 and not more than 150,000. .

2. The heat-shrinkable polyester tube according to claim 1, wherein the thermoplastic polyester resin composition is a resin composition containing a polyethylene terephthalate resin as a main component.

3. The heat-shrinkable polyester-based tube according to claim 1, wherein the hydrolysis inhibitor is a monomer or polymer of a carpoimide compound.

4. The method according to claim 1, wherein the hydrolysis inhibitor is contained in a ratio of 0.3 to 5.0 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin. Item 4. The heat-shrinkable polyester tube according to item 3.

5. The hydrolysis inhibitor is a bullet polymer containing, as a constituent unit, a monomer unit having a functional group reactive with at least one of a group consisting of a carboxyl group and a hydroxyl group. The heat-shrinkable polyester-based tube according to claim 1 or 2, wherein

6. The heat-shrinkable polyester tube according to claim 5, wherein the functional group is an epoxy group.

7. The compounding amount of the hydrolysis inhibitor is the thermoplastic polyester resin. 9. The composition according to claim 1, wherein the content is in a range satisfying a relationship of 97 to 80% by mass and a hydrolysis inhibitor of 3 to 20% by mass. Item 6. The heat-shrinkable polyester tube according to any one of items 1.

8. The range of claims 1 to 7 wherein the molecular weight retention of the heat-shrinkable polyester-based tube formed from the thermoplastic polyester-based resin composition satisfies the following formula: The heat-shrinkable polyester tube according to claim 1. Molecular weight retention = Mw (30) / M (0) ≥ 0.4

(Where Mw (0) is the initial weight-average molecular weight in terms of polystyrene determined by gel permeation chromatography of the heat-shrinkable polyester tube, and Mw (30) is the heat-shrinkable tube. After coating, heat after 30 hours of treatment at 130 ° C, 85% relative humidity and 0.23 Mpa absolute vapor pressure according to JISC 096 (This is the weight average molecular weight in terms of polystyrene of the shrinkable polyester-based tube, as determined by genolepermeation chromatography.)

9. When the heat-shrinkable polyester tube is immersed in warm water of 98 ± 2 ° C for 30 seconds, the heat shrinkage ratio is 30 to 70% in the radial direction and 0 to 70 in the length direction. 9. The heat-shrinkable polyester tube according to any one of claims 1 to 8, wherein the heat-shrinkable polyester tube is 40%.

10. A capacitor product characterized by being coated with the heat-shrinkable polyester-based tube according to any one of claims 1 to 9.