JPH0784552B2 - Shape memory resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is excellent in physical properties such as strength properties and impact resistance.
It is intended to provide a resin composition which exhibits high shape recovery characteristics by heating treatment and is excellent in processability such as injection molding.
Specifically, as a polymer component (A), the glass transition temperature is 50 ° C.
1.4-having crystallinity at 25 ° C sandwiched between two or more vinyl aromatic hydrocarbon polymer blocks
The present invention relates to a shape memory resin composition containing a block copolymer having a structure including at least one set of trans-conjugated diene polymer blocks in a polymer chain and an aromatic polymer.

[Conventional technology]

Or sequentially polymerizing a vinyl aromatic monomer and a conjugated diene monomer by using a living polymerization characteristics of the polymerization catalyst using I _A metal compound of an organic lithium, or perform terminal coupling reaction if necessary It is already well known to obtain a block copolymer of a vinyl aromatic monomer and a conjugated diene monomer. These block copolymers are called thermoplastic elastomers when the content of the vinyl aromatic compound is relatively small, and are widely used in the fields of rubber materials, plastic modifiers, adhesives and the like. Further, when the content of the vinyl aromatic compound is relatively large, a thermoplastic resin excellent in transparency and impact resistance is obtained, and is widely used mainly in the field of food packaging containers. However, the trans-bond content of the conjugated diene portion of the copolymer obtained by such a production method does not usually exceed 60%, and a block copolymer having a crystalline trans-conjugated diene polymer block cannot be obtained. It was

On the other hand, it is known that a conjugated diene polymer having a high trans-1.4-bond content can be conventionally produced by the following three kinds of techniques.

(1) A manufacturing technique using a so-called Ziegler catalyst containing a transition metal compound as a main component.

(2) A manufacturing technique using an anionic polymerization catalyst system containing an alkaline earth metal compound as a main component.

(3) A manufacturing technique using a catalyst system containing a rare earth metal compound as a main component.

However, in order to obtain a crystalline polymer having a high stereoregularity in which the trans bond content of the conjugated diene portion exceeds 80% by these techniques, it is generally necessary to lower the polymerization temperature and the polymerization activity is low. It becomes a thing. In particular, when trying to block-copolymerize a conjugated diene monomer and a vinyl aromatic monomer, it is necessary to complete the reaction in each block of the polymerization reaction, which requires high polymerization activity and high living property at the polymerization active terminal. To be done. Therefore, it has not been possible to obtain a crystalline block copolymer having a structure as used in the present invention.

[Problems to be solved by the invention]

As described above, the conventional technique of using a polymerization catalyst has a problem in its catalytic property, and therefore, it is sandwiched between two or more vinyl aromatic compound polymerization blocks, which are the objects of the present invention.
It has not been possible to obtain a block copolymer containing a crystalline conjugated diene polymer block having a 1,4-trans bond content of 80% or more in the conjugated diene part in the polymer chain. Nothing was known about this type of polymer and its properties.

[Means and Actions for Solving Problems]

Under such circumstances, the present inventor developed a method for producing a copolymer containing a crystalline trans-conjugated diene polymer block and a vinyl aromatic compound polymer block, and obtained a crystalline block copolymer. Further, as a result of intensive studies on a composition containing this crystalline block copolymer, it has excellent miscibility as a polymer component with this crystalline block copolymer and a vinyl aromatic compound polymer block of the same block copolymer. A composition comprising an aromatic polymer retains the characteristics that the crystalline block copolymer originally has excellent strength, impact resistance, shape memory property, and the like, and its flowability is improved so that molding, processability, and In particular, they have found that they have excellent injection moldability and have reached the present invention.

That is, the present invention relates to an aromatic polymer 3 containing (A) 97 to 30% by weight of the following crystalline block copolymer and (B) at least 10% by weight of a monomer having an aromatic nucleus in the polymer chain. ~
A shape memory resin composition containing 70% by weight is provided.

(A) in the polymer component of the shape memory resin composition of the present invention
Those crystalline block copolymer as the component comprising a star structure represented by the general formula triblock chain or (D-E _n X represented by the general formula of at least A-B-C in the polymer chain Where A, C and D in the general formula are homopolymers of vinyl aromatic compounds having a glass transition temperature of 50 ° C. or higher and a weight average molecular weight of 2,000 to 100,000, or vinyl aromatic compounds and other vinyl aromatic compounds. It is a block composed of a copolymer with a group compound or a conjugated diene compound.

If the glass transition temperature of the A, C and D blocks is less than 50 ° C., the physical properties of the resulting composition, such as strength and elongation, are significantly reduced, which is not preferable. When the weight average molecular weight is less than 2,000, the physical properties such as strength and elongation of the composition are deteriorated, which is not preferable, and when it exceeds 100,000, the processability of the composition is significantly decreased, which is not preferable.

The blocks A, C and D are preferably a homopolymer of a vinyl aromatic compound or a copolymer of a vinyl aromatic compound and another vinyl aromatic compound, but the block of the vinyl aromatic compound and the conjugated diene compound is It may be a random or tapered copolymer.

The blocks of B and E have the respective weight average molecular weights.
It is in the range of 25,000 to 1,000,000 or in the range of 10,000 to 500,000, has a glass transition temperature of 10 ° C or lower, has crystallinity at 25 ° C, and has a 1,4-trans bond content of the conjugated diene portion of 80.
% Or more of a homopolymer of a conjugated diene compound, or a block of a copolymer of a conjugated diene compound and another conjugated diene compound or a copolymer of a conjugated diene compound and less than 20% by weight of a vinyl aromatic compound. .

The weight average molecular weight of the block B is less than 25,000 or E
If the weight average molecular weight of the block is less than 10,000, physical properties such as elongation and impact resilience of the resulting composition are deteriorated, which is not preferable. The weight average molecular weight of each block of B and E is 1,0
If it exceeds 00,000 or 500,000, the processability of the resulting composition is significantly deteriorated, which is not preferable.

Further, if the glass transition temperature of the B and E blocks exceeds 10 ° C., the impact resilience and shape memory properties of the resulting composition are deteriorated, which is not preferable.

Blocks B and E must have crystallinity at 25 ° C. That is, its melting point must be above 25 ° C. The melting points of the blocks B and E are preferably 25 ° C. or higher and not higher than the glass transition of the blocks A and C or the block D of the corresponding polymer, particularly preferably 10 ° C. or lower of the glass transition temperature thereof.

If the blocks B and E do not have crystallinity at 25 ° C,
The composition obtained is unfavorable because the hardness and strength are lowered, and the shape memory characteristics are remarkably lowered.

In addition, the conjugated diene part of the blocks of B and E
Even if the 4-trans bond content is less than 80%, the strength and elongation of the obtained composition are lowered, and the shape memory characteristics are remarkably lowered, which is not preferable.

Further, the blocks B and E are homopolymers of conjugated diene compounds, copolymers of conjugated diene compounds with other conjugated diene compounds, or copolymers of conjugated diene compounds with less than 20% by weight of vinyl aromatic compounds. If the content of the vinyl aromatic compound in the block exceeds 20% by weight, the impact resilience and the shape memory property of the resulting composition are deteriorated, which is not preferable. The mode of the copolymerization may be random copolymerization or taper copolymerization.

In the crystalline block copolymer of the present invention, in the polymer chain, in addition to the A, B, C blocks or D, E blocks, between or outside each block of the structure not specified in the present invention. Block, eg, 1,4-trans coupling content is 80
%, A conjugated diene polymer block or the like may be contained to such an extent that the basic characteristics of the polymer of the present invention are not lost.

In the general formula showing the structure of the crystalline block copolymer of the present invention, n is an integer of 2 or more and 10 or less. When n is 1, physical properties such as strength and elongation of the resulting composition are remarkably deteriorated and shape memory characteristics are deteriorated, which is not preferable, and when n is 11 or more, workability is remarkably deteriorated, which is not preferable. X is a terminal coupling agent, which is generally selected from coupling agents used in the terminal coupling reaction in anionic polymerization of conjugated dienes.

Examples of the monomer constituting the crystalline block copolymer of the present invention include styrene, α-methylstyrene, p-methylthretin, m-methylthretin, o as a vinyl aromatic compound.
-Methylstyrene, p-tert-butylstyrene, dimethylstyrene, vinylnaphthalene, etc. are mentioned, and butadiene, isoprene, piperylene etc. are mentioned as a conjugated diene compound. Particularly preferred monomers are styrene and butadiene.

Crystalline block copolymer, in addition to the general formula A-B-C triblock copolymer or the general formula (D-E _n X star-shaped block copolymer, impurities produced during naturally polymerization For example, it may contain a 1,4-trans conjugated diene polymerization, a vinyl aromatic compound polymer, or a diblock copolymer composed of a 1,4-trans conjugated diene polymerization block and a vinyl aromatic compound block. . But if not star-shaped block copolymers of this case, even a-B-C triblock copolymer or (D-E _n X is contained 30 wt% or more, can not be expressed sufficiently the effects of the present invention .

The aromatic polymer which is the component (B) of the shape-memory resin composition of the present invention must contain at least 10% by weight of a monomer having an aromatic nucleus in the polymer chain by copolymerization. I won't. When the content of the monomer having an aromatic nucleus is less than 10% by weight, miscibility with the crystalline block copolymer which is the component (A) of the composition of the present invention becomes poor and various properties such as strength and shape memory property are obtained. It is not preferable because the physical properties are deteriorated.

Further, the molecular weight of the aromatic polymer is not particularly limited, but generally 500 to 500,000 depending on the composition and use of the composition.
It is preferably in the range of. Particularly preferably 1,000 to 1
It is in the range of 00,000. When the molecular weight is less than 500, the rigidity and strength of the composition may be slightly lowered, and when the molecular weight exceeds 500,000, the processability may be lowered.

Further, the glass transition temperature of the aromatic polymer is not particularly limited, but it is generally preferably in the range of 25 ° C to 250 ° C. Depending on the conditions, when the glass transition temperature is lower than 25 ° C, the rigidity and shape memory property are deteriorated, and when it is 250 ° C or higher, the workability is deteriorated, which is not preferable in some cases.

Preferred examples of aromatic polymers include styrene polymers, styrene-butadiene copolymers, α-methylstyrene polymers, p-methylstyrene polymers, o-methylstyrene polymers, p-tert-butylstyrene polymers. Examples include coalesce, polyphenylene ether, coumarone-indene resin, and the like.

In the shape-memory resin composition of the present invention, the content of the crystalline block copolymer which is the component (A) as a polymer component is in the range of 97 to 30% by weight. The content of component (A) is
If it is less than 30% by weight, the excellent shape memory property, which is one of the features of the present invention, cannot be sufficiently exhibited, and if it exceeds 97%, it is possible to form, process and The effect of improving rigidity is not sufficient.

In the shape-memory polymer component of the present invention, an inorganic filler or a plasticizer may be blended, if necessary, in addition to the above polymer component in order to adjust hardness, plasticity and the like. In addition, stabilizers and pigments, which are general additives to be added to the polymer resin material, can be appropriately added in the case of the present invention as in the conventional resin material.

The amount of inorganic filler used is from 5 to 100 parts by weight per 100 parts by weight of polymer component. Examples of inorganic fillers include titanium oxide, calcium carbonate, clay, talc, mica,
Examples thereof include bentonite, silica, carbon and the like. 100
Use of an inorganic filler in excess of parts by weight reduces the impact strength of the resulting polymer resin material, which is not preferable.

The amount of plasticizer used is usually in the range of 1 to 20 parts by weight per 100 parts by weight of polymer component. Examples of plasticizers include:
Dibutyl phthalate, di- (2-ethylhexyl) phthalate, di- (2-ethylhexyl) adipate, diethylene glycol dibenzoate, butyl stearate, butyl epoxy stearate, tri- (2-ethylhexyl) phosphate, various petroleum oils and the like can be mentioned. .

The crystalline block copolymer of the present invention is an extruder, kneader,
It can be easily mixed with a roll or the like. The set temperature of these devices can be freely selected within the range of 60 to 200 ° C, but it is preferably set to 80 to 180 ° C. Alternatively, they can be dissolved in a suitable solvent and mixed in a solution.

The shape-memory resin composition obtained in this manner has its features, namely, physical properties such as shape-memory characteristics, rigidity, strength, and impact resistance, and processing characteristics such as injection moldability, low-temperature processability, and reworkability. It can be utilized for various resin materials by making the best use of it.

For example, (1) Mainly, it is excellent in rigidity and impact resistance, and it is easy to process or partly repair it at a relatively low temperature, that is, by touching human skin or by hand, so that splints, casts, etc. Fixing materials for medical parts and protectors for sports, (2) Cold stretching or heat stretching after extrusion into a sheet shape, preferably glass of corresponding A, C or D block of crystalline block copolymer A heat-sensitive shrinkable film or a laminate (laminate film) stretched at a temperature not higher than the transition temperature and not lower than a normal temperature, (3) after being molded into a cylindrical shape or other various shapes by injection molding or extrusion molding, Heat-shrinkable sleeve stretched and expanded under the conditions, focusing of coupling device or heat-shrinkable wire, insulating tube, (4) Toys, dolls, artificial flowers or heat-sensitive sensors using them, which make use of the shape memory characteristics of recovering the shape from the deformed shape to the original shape injection-molded or compression-molded when a certain temperature is reached, (5) Molding processing After memorizing a rough shape in advance by using, various mold-collecting materials that take advantage of the features that it is easy to fit to the mold surface by heat shrinkage or shape recovery and to easily heat or modify details touching human skin It can be used as a head material for wigs.

〔The invention's effect〕

As described in detail above, the present invention has various excellent properties useful as a resin, such as rigidity, strength, and impact resistance, and also has excellent shape memory properties, and is easy to mold and process, and particularly injection molding. It is intended to provide a resin composition having features of excellent moldability and low-temperature processability.

〔Example〕

The present invention will be specifically described below with reference to Examples, but the scope of the present invention is not limited thereto.

In. This example was obtained crystalline block copolymer represented by general formula (D-E _n X by the manufacturing method disclosed in Examples 1-11 Application No. Showa No. 61-33945, D in the formula Is a polystyrene block, E is a transbutadiene block, X is diphenyl carbonate, and n is 3.

As a result of the analysis, the D part shows a glass transition temperature of 93 by a differential thermal analyzer.
℃, gel permeation chromatograph weight average molecular weight 9,200, E section is a differential thermal analyzer melting point 6
8 ℃, glass transition temperature −90 ℃, 1.4-trans bond content calculated by Hampton method using infrared spectrophotometer 87
%, And the weight average molecular weight by gel permeation chromatography was 21,000. Weight average molecular weight as a whole
89,000, a crystalline block copolymer having a styrene content of 30% by weight and containing 7% of polystyrene, trans polybutadiene and styrene-butadiene diblock polymer as impurities.

This crystalline block copolymer is a composition shown in Table 1 and a low melting point crystalline polymer, an inorganic filler or a plasticizer and a Labo Plastomill * (1) set at 150 ° C. After kneading for minutes, the physical properties of the composition were evaluated. The obtained results are shown in Table-1.

* (1) Toyo Seiki Seisakusho Co., Ltd. (1) Polystyrene having a weight average molecular weight of 85,000 and a glass transition temperature of 98 ° C (2) Polyphenylene ether having a weight average molecular weight of 12,000 and a glass transition temperature of 210 ° C (3) Tufden 4003 (styrene-produced by Asahi Kasei Corporation)
(Butadiene copolymer rubber), glass transition temperature of styrene block 89 ° C (4) Weight average molecular weight 17,000, glass transition temperature 113 ° C Poly-
α-Methylstyrene (5) Titanium White A-100 (manufactured by Ishihara Sangyo Co., Ltd.) (6) Fine powder talc (7) Nipsil VN3 (manufactured by Nippon Silica Industry Co., Ltd.) (8) Measured by JIS K-6301 ( 9) Test temperature 190 ℃, test load 2.16Kg (10) Width 5mm, thickness 2mm, length 10cm test piece is folded at 180 ℃ at an angle of 180 ℃, and the shape is fixed by rapid cooling to 20 ℃. To do. Next, the temperature of the test piece is gradually raised, and the temperature at which the angle becomes 90 ° is taken as the shape recovery temperature. The temperature was further raised to 80 ° C and the degree of recovery of the turning angle was expressed by the recovery rate.

Examples 12 to 14 Crystalline block copolymers represented by the general formula ABC were obtained by the production method disclosed in Application No. SHO 61-57096. The structure of the obtained crystalline block copolymer is shown in Table-2.
Shown in.

These crystalline block copolymers were kneaded with an aromatic polymer having the composition shown in Table 3 under the same conditions as in Example 1 using a Labo Plastomill set at 150 ° C, and the physical properties thereof were evaluated.
The physical property evaluation conditions are the same as those in Table-1. The obtained results are shown in Table-3.

Example 15 80 parts of the crystalline block copolymer shown in Example 1 and polystyrene (weight average molecular weight 69,000, glass transition temperature 97 ° C.) 20
22 cm tall using an injection molding machine set at 150 ° C using a shape-memory resin material composed of 10 parts and 10 parts talc
I got an upright shape doll. This doll deformed while being heated with warm water at 60 ° C, and could be freely deformed into various postures by cooling and fixing. In addition, again after deformation
By immersing in warm water at 70 ° C and heating, it was possible to completely restore the original upright shape doll.

Example 16 A shape-memory resin material having the same composition as in Example 4 was used.
mm extruder at a set temperature of 150 ° C. to extrude strands with a diameter of 3 mm. The extruded strand immediately has a diameter of 15 mm
It was wound around a Teflon rod, cooled, and formed into a coil. When this coil was stretched in warm water at 50 ° C. and returned to room temperature as it was, the stretched shape was fixed. However, when this was immersed again in warm water at 60 ° C, the shape was completely restored to the original coil shape.

Example 17 80 parts of the crystalline block copolymer shown in Example 1 and poly-
A shape memory resin material having a composition of 20 parts of α-methylstyrene (weight average molecular weight: 17,000, glass transition temperature: 113 ° C) was extruded by a 20 mm extruder at a set temperature of 150 ° C,
A tube with an inner diameter of 3 mmφ and a wall pressure of 0.8 mm was molded. Then 70
The tube was evacuated at 0 ° C. to expand the tube in the circumferential direction by 200% (3 times diameter).

The obtained tube had a tensile strength of 330 Kg / cm ^{2 at} room temperature, a breaking elongation of 440%, a radial heat shrinkage rate of 190% after immersion in hot water at 70 ° C for 1 minute (residual strain of 10%), and a constant temperature bath at 40 ° C of 1 It had a natural shrinkage rate of 2.7% after a week, and had good properties as a heat shrinkable tube that could be used for the assembly of electrical wiring and insulation protection.

Example 18 150 parts of the shape-memory resin material having a composition consisting of 50 parts of the crystalline block copolymer, 50 parts of a styrene-butadiene copolymer (Tufden 4003: supra) and 30 parts of talc shown in Example 1 was used.
An arm cast molding was obtained by compression molding at ℃.

This arm cast molding was immersed in warm water at 50 ° C to heat and soften it, and the arm was partially corrected to form a cast. This cast material could be easily cast in a short time by molding and storing a rough shape in advance.

This cast material also has a tensile strength at room temperature ^{* 1 of} 240 kg / cm.
² , the flexural modulus was 2150 Kg / cm ^{2 * 2} .

* 1 According to JIS K 7113 * 2 According to ASTM D 790

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Claims (13)

[Claims] 1. At least AB- in the polymer chain (A).
A triblock chain represented by the general formula of C, or (D-
Crystalline block copolymer comprising a star structure represented by the general formula E _n X wherein, A, C and D glass transition temperature 50 ° C. or higher, the vinyl aromatic in the range of weight average molecular weight from 2,000 to 100,000 compounds Is a block composed of a homopolymer of the above, or a copolymer of a vinyl aromatic compound with another vinyl aromatic compound or a conjugated diene compound, and A and C may have the same structure or different structures. B and E have crystallinity at a glass transition temperature of 10 ° C. or lower and 25 ° C., and when the weight average molecular weight is B, they are in the range of 25,000 to 1,000,000.
In the case of 1, the range is 10,000 to 500,000, and a homopolymer of a conjugated diene compound having a 1,4-trans bond content of the conjugated diene portion of 80% or more, or a copolymer of the conjugated diene compound and another conjugated diene compound is used. Polymer or conjugated diene compound
It is a block composed of a copolymer with less than 20% by weight of a vinyl aromatic compound. X is an end coupling agent, n
Is an integer of 2 or more and 10 or less. A shape memory resin composition containing 97 to 30% by weight and (B) 3 to 70% by weight of an aromatic polymer containing at least 10% by weight of a monomer having an aromatic nucleus in the polymer chain. 2. The aromatic polymer as the component (B) has a molecular weight of 50.
The shape memory resin composition according to claim 1, wherein the glass transition temperature is in the range of 0 to 500,000 and 25 to 250 ° C. 3. The vinyl aromatic monomer constituting the component (A) is styrene, and the conjugated diene monomer is 1,3-butadiene. The shape memory resin composition according to item 2. 4. The shape-memory resin composition according to any one of claims 1 to 3, wherein the component (B) is polystyrene. 5. The shape-memory resin composition according to any one of claims 1 to 3, wherein the component (B) is polyphenylene ether. 6. The shape-memory resin composition according to any one of claims 1 to 3, wherein the component (B) is a styrene-butadiene copolymer. 7. The shape-memory resin composition according to any one of claims 1 to 3, wherein the component (B) is poly-α-methylstyrene. 8. The shape memory property according to any one of claims 1 to 7, wherein an inorganic filler is added in an amount of 5 to 100 parts by weight based on 100 parts by weight of the polymer component. Resin composition. 9. At least AB- in the polymer chain (A).
A triblock chain represented by the general formula of C, or (D-
Crystalline block copolymer comprising a star structure represented by the general formula E _n X wherein, A, C and D glass transition temperature 50 ° C. or higher, the vinyl aromatic in the range of weight average molecular weight from 2,000 to 100,000 compounds Is a block composed of a homopolymer of 1 or a copolymer of a vinyl aromatic compound and another vinyl aromatic compound or a conjugated diene compound, and A and C may have the same structure or different structures. B and E have crystallinity at a glass transition temperature of 10 ° C. or lower and 25 ° C., and when the weight average molecular weight is B, they are in the range of 25,000 to 1,000,000.
In the case of 1, the range is 10,000 to 500,000, and a homopolymer of a conjugated diene compound having a 1,4-trans bond content of 80% or more in the conjugated diene portion, or a copolymer of the conjugated diene compound with another conjugated diene compound is used. Polymer or conjugated diene compound
It is a block composed of a copolymer with less than 20% by weight of a vinyl aromatic compound. X is an end coupling agent, n
Is an integer of 2 or more and 10 or less. A shape memory resin composition containing 97 to 30% by weight and (B) 3 to 70% by weight of an aromatic polymer containing at least 10% by weight of a monomer having an aromatic nucleus in the polymer chain is injected. A molded product obtained by molding, extrusion molding, or compression molding. 10. The molded article according to claim 9, wherein the shape memory resin composition is the composition according to any one of claims 2 to 8. 11. A molded article is selected from a medical fixing material for an affected area, a sports protector material, a toy, a doll, an artificial flower and a molding material, and a wig head molding material. The molded article according to item 9 or 10 in the range. 12. At least AB in the polymer chain (A).
A triblock chain represented by the general formula of -C, or (D
Crystalline block copolymer comprising a star structure represented by the general formula -E _n X wherein, A, C and D glass transition temperature 50 ° C. or higher, the vinyl aromatic in the range of weight average molecular weight from 2,000 to 100,000 A block composed of a homopolymer of a compound or a copolymer of a vinyl aromatic compound and another vinyl aromatic compound or a conjugated diene compound, and A and C may have the same structure or different structures. . B and E have crystallinity at a glass transition temperature of 10 ° C. or lower and 25 ° C., and when the weight average molecular weight is B, they are in the range of 25,000 to 1,000,000.
In the case of 1, the range is 10,000 to 500,000, and a homopolymer of a conjugated diene compound having a 1,4-trans bond content of 80% or more in the conjugated diene portion, or a copolymer of the conjugated diene compound with another conjugated diene compound is used. Polymer or conjugated diene compound
It is a block composed of a copolymer with less than 20% by weight of a vinyl aromatic compound. X is an end coupling agent, n
Is an integer of 2 or more and 10 or less. A shape memory resin composition containing 97 to 30% by weight and (B) 3 to 70% by weight of an aromatic polymer containing at least 10% by weight of a monomer having an aromatic nucleus in the polymer chain is injected. A heat-shrinkable molded product obtained by stretching or expanding a molded product obtained by molding, extrusion molding, or compression molding. 13. The heat-shrinkable molded product is selected from heat-shrinkable coupling devices, sleeves, wire coatings, binding tubes, films, and laminates. A molded article having heat shrinkability according to item 12.