JPH0796597B2 - Method for manufacturing shape memory resin molded body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a method for producing a shape-memory resin molded article having excellent heat-sensitive shape memory characteristics.

More specifically, the present invention provides a block copolymer having a specific structure,
A shape that has excellent heat-sensitivity, obtained by forming by the usual processing method used for plastics, deforming in a specific temperature range, and fixing the strain by cooling. The present invention relates to a method for manufacturing a memory resin molded body.

[Prior Art] As a material having shape memory characteristics, a shape memory alloy is already widely known. Examples of this type include Cu-Al-Ni alloys, Au-Cd alloys, In-Ti alloys, Ni-Ti alloys and the like. Although these shape-memory alloys have excellent heat-sensitive shape-memory characteristics, the materials are very expensive, or the heat treatment or processing for exerting the shape-memory characteristics is not always easy. It has not been widely used for any purpose other than its intended purpose.

On the other hand, several types of polymers have already been known as resins having thermosensitive shape memory performance. These are structurally
It can be classified into a cross-linked product of a polymer having an appropriate melting point or glass transition temperature above room temperature, or a cold-worked product of a polymer having an appropriate melting point or glass transition temperature above room temperature and a remarkably high molecular weight.

Generally, a polymer material in the temperature range below the glass transition temperature or the melting point is restricted in the thermal motion of the molecular chain, and exhibits a property as a hard resin. However, when it is heated above the glass transition temperature or above the melting point, it becomes a so-called rubber-like substance. This kind of temperature dependence is a property common to all polymer materials. From a practical point of view, there are many points to consider such as the glass transition temperature or the melting point temperature range and the easiness of plastic deformation, but most high cross-linking points with some substantial cross-linking points are not relaxed. It can be said that molecular materials have a certain degree of shape memory.

That is, a resin molded product of a certain kind of polymer is produced by various molding methods, and a crosslinking reaction is performed after the molding in order to memorize the shape. When this molded product is heated to a temperature higher than its glass transition temperature or melting point to be deformed and the temperature is lowered to the glass transition temperature or melting point or lower while being deformed, the strain is maintained. This is because at a temperature below the glass transition temperature or melting point, the thermal motion of the molecular chains is restricted,
This is because the distortion is fixed. When the deformed molded product is heated again to a glass transition temperature or a temperature equal to or higher than the melting point at which the thermal movement of the molecular chains is possible, the strain is released and the original shape is restored.

As this kind of shape memory resin, a crosslinked product of crystalline polyolefin (US Pat. No. 3,082,642), a crosslinked product of crystalline transpolyisoprene (JP-A-61-16956), and a crosslinked product of crystalline transpolybutadiene (US Pat. No. 3,139468). No.) and the like are known. Among polyolefins, a crosslinked product of crystalline polyethylene has been put to practical use in applications such as heat-shrinkable tubes. However, in these crystalline polymers, since crystallization is not hindered by cross-linking, it is necessary to carry out cross-linking by low temperature vulcanization or radiation irradiation in a crystallized state of the polymer, which exerts shape memory properties. Therefore, this type of shape memory resin has not been widely used except for specific applications.

Further, when the polymer has a remarkably high molecular weight, the entanglement of the polymer molecular chains becomes a substantial cross-linking point and the strain is not relaxed and the shape memory function is exhibited even at a temperature of the glass transition temperature or higher. Examples of this type of shape memory resin include polynorbornene (JP-A-59-53528), polyvinyl chloride,
Polymethyl methacrylate, polycarbonate, AB resin, etc. are known.

However, this type of polymer has a remarkably high molecular weight (for example, 2,000,000) in order to sufficiently exhibit the shape memory function.
Above), inevitably the fluidity of the polymer is significantly lowered in this case, and it becomes extremely difficult to process by a general-purpose plastic processing machine such as injection molding or extrusion molding. There is also a technology of cold working (deformation at a temperature below the glass transition temperature) by setting the molecular weight lower than this, but it requires a special operation and has a difficult problem such as poor processing productivity. It has, and is not yet widely used.

A shape memory resin utilizing a block copolymer has already been developed as a technique of a new idea for improving the problems in processability and the like which were inevitable in the conventional techniques using these polymers. Examples of this include the shape memory resin containing a crystalline block copolymer composed of styrene and butadiene disclosed in JP-A-62-275114. This resin can be sufficiently processed by a general-purpose plastic processing machine and has achieved excellent shape memory. However, since this shape-memory resin contains many unsaturated bonds in the polymer chain, it has a problem in heat resistance and weather resistance when industrial applications are considered.

In addition, the shape of the polymer material can be adjusted by pH, chelate formation,
A method of reversibly isothermally deforming by utilizing chemical energy such as redox reaction and a method of reversibly isothermally changing by utilizing a photoreaction of a photofunctional group in a polymer material are also widely known. It has not been put to practical use.

[Problems to be Solved by the Invention] The present invention has the above-mentioned drawbacks of conventional shape memory materials, that is, it is difficult to apply a general-purpose plastic processing method such as injection molding or extrusion molding, and a low-temperature crosslinking reaction occurs. As a result, a method for producing a shape-memory resin molded body that solves the problem of complicated handling as a result of requiring special operations such as above, and that also has excellent performance as a resin material such as heat resistance and weather resistance It is the one we are trying to provide.

[Means and Actions for Solving the Problems] As a result of earnest studies on the method for producing a heat-sensitive shape-memory resin molded product for solving the above problems, the present inventor found that a block copolymer having a specific structure was selected. After being processed and molded by a general-purpose plastic processing machine such as injection molding, extrusion molding, etc., the molded body reshaped into a shape different from the above under certain conditions does not have any shape for giving a shape such as a crosslinking reaction. The inventors have found that the present invention has extremely excellent shape memory performance without requiring any special operation, and have reached the present invention.

That is, the present invention provides a block copolymer having a weight average molecular weight in the range of 10,000 to 1,000,000 containing an ABA block structure consisting of at least the polymer blocks A and B specified below in the A block. The present invention relates to a method for producing a shape-memory resin molded product, which comprises molding into a desired shape at a temperature exceeding the glass transition temperature of, and remolding into a shape different from the above at a temperature lower than the glass transition temperature of the A block. is there.

Specific examples of the block copolymer structure include the general formula (a) (AB) _n A (b) B (AB) _n A (c) B (AB) _n AB (d) [(AB) _n ] _m X (e) [(AB) _n A] _m X (f) [B (AB) _{n] m} X (g) [B (AB) _n A] _m X The chain block structure, the star block structure or the graft type block structure represented by can be mentioned.

In the above formula, n is an integer from 1 to 10 and m is 2
As described above, it is an integer of 10 or less, X is an end coupling agent, and each A block and each B block may have the same structure or different structures. The A block comprises a homopolymer of a vinyl aromatic compound, a copolymer of a vinyl aromatic compound with another vinyl aromatic compound, a copolymer of a vinyl aromatic compound with a conjugated diene compound, or a hydrogenated product thereof. . When the A block is a copolymer, the copolymerization mode may be any copolymerization mode such as random copolymerization, alternating copolymerization, taper copolymerization, and is not particularly limited. Particularly when the A block is a copolymer of a vinyl aromatic compound and a conjugated diene compound or a hydrogenated product thereof, the content of the vinyl aromatic compound or a hydrogenated product thereof is preferably 70% by weight or more. The glass transition temperature of the A block must be 50 ° C. or higher, preferably 65 ° C. or higher and 250 ° C. or lower, more preferably 80 ° C. or higher and 200 ° C. or lower. When the glass transition temperature is lower than 50 ° C., the natural relaxation of the memorized shape at room temperature remarkably occurs, and the shape memory characteristic is deteriorated, which is not preferable. If the glass transition temperature is too high, it becomes difficult to process the resin by a general-purpose plastic processing machine, which is not preferable in some cases. Furthermore, the preferable range of the weight average molecular weight of the A block is 1,00.
The range is 0 to 100,000, and more preferably 3,000 to 30,000. An excessively high molecular weight causes the resulting block copolymer to have a high molecular weight and thus a high melt viscosity,
It causes deterioration of workability. In addition, the excessively low molecular weight may cause the phase-separated structure of the A and B blocks of the block copolymer to collapse, and the shape memory performance of the resulting molded article may not be sufficiently exhibited.

The B block is composed of a homopolymer of a conjugated diene compound, a copolymer of a conjugated diene compound and another conjugated diene compound, or a copolymer of a conjugated diene compound and a vinyl aromatic compound, and the conjugated diene unit is unsaturated. More than 50 mol% of the bonds are hydrogenated products, and the crystallinity at 25 ° C is B
More than 5% by weight of the polymer block and at least 50% by weight of its crystals melt below the glass transition temperature of the A block. When the B block is a copolymer, the bonding mode may be any copolymerization mode such as random copolymerization or taper copolymerization, and is not particularly limited. Particularly when the B block is a hydrogenated product of a copolymer of a conjugated diene compound and a vinyl aromatic compound, the content of the conjugated diene and its hydrogenated product is preferably 70% by weight or more. Further, 50 mol% or more of the unsaturated bonds of the conjugated diene unit must be a hydrogenated product, and the preferable hydrogenation rate is 75 mol% or more, more preferably 95 mol% or more, most preferably 98 mol% or more. . If the hydrogenation rate is less than 50 mol%, sufficient crystallinity cannot be imparted to the obtained block copolymer, and shape memory performance is not exhibited. When the hydrogenation rate is 98 mol% or more,
The heat resistance and weather resistance of the obtained molded product are remarkably improved, which is particularly preferable. Furthermore, the crystallinity of the B block at 25 ° C must be 5% by weight or more, and the preferable crystallinity is
It is 10% by weight or more, and more preferably 30% by weight or more.
If the crystallinity is less than 5% by weight, the polymer will exhibit remarkable rubber elasticity and it will be difficult to impart a shape memory. Also, at least 50% by weight of the crystals at 25 ° C must melt below the glass transition temperature of the A block. Preferably 80% by weight, more preferably 95% by weight, are those in which the crystals melt below the glass transition temperature of the A block. When the melting temperature of 50% by weight or more of the crystals exceeds the glass transition temperature of the A block, the shape memory performance of the obtained molded product is significantly deteriorated. The weight average molecular weight of the B block is preferably 2,000 to 500,000, more preferably
It is in the range of 4,000 to 200,000. An excessively high molecular weight causes the resulting block copolymer to have a high molecular weight and thus a high melt viscosity, resulting in poor processability. In addition, the excessively low molecular weight may be because the phase-separated structure of the A and B blocks of the block copolymer may be destroyed, so that the obtained molded product does not sufficiently exhibit the shape memory property.

The weight average molecular weight of the block copolymer as a whole is 10,0.
Must be in the range 00 to 1,000,000. A preferred weight average molecular weight is 15,000 to 300,000, particularly preferably 20,00.
It is in the range of 0 to 150,000. An excessively high molecular weight causes a high melt viscosity, resulting in poor processability. Further, an excessively low molecular weight is not preferable because it deteriorates the performance of the resin such as strength and rigidity. The composition ratio of the A and B blocks is
A block content is preferably 5 to 70% by weight, more preferably 10 to 60% by weight, and particularly preferably 20 to 45% by weight.
Is the range. If the composition ratio of the A and B blocks is outside this range, sufficient memory performance cannot be exhibited.

The block copolymer used in the method for producing a shape-memory resin molded product of the present invention can be obtained by applying known techniques. For example, Japanese Patent Publication No. 40-23798, Japanese Patent Publication No.
40-24914 or Japanese Examined Patent Publication No. 46-3990, etc., a monomer selected from the corresponding vinyl aromatic compound and conjugated diene compound or a mixture thereof is sequentially polymerized by an anionic polymerization method, etc. Can be obtained by carrying out a hydrogenation reaction on the unsaturated bond, for example, by the method shown in JP-A-58-109515 or JP-B-63-4841 after carrying out various polymer reactions by .

N relating to the number of blocks defining the structure of the block copolymer used in the present invention is 1 to 10, preferably 1 to 5
And m, which indicates the number of branches in the star polymer, is 2 to
The range is 10, preferably 2 to 4. Further, it goes without saying that it may be a mixture of polymers in which n and m are different.

Examples of preferred vinyl aromatic compounds used in producing these block copolymers are styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-tert-butylstyrene, Examples thereof include dimethylstyrene, vinylnaphthalene, and diphenylethylene. Examples of preferable conjugated diene compounds used include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene and 2,4-hexadiene. A particularly preferred vinyl aromatic compound is styrene. A particularly preferred conjugated diene compound is 1,3-butadiene, and the bonding mode of 1,3-butadiene is 80% or more of 1,4-bonds.

The block copolymer used in the method for producing a shape-memory resin molded product of the present invention exhibits the following temperature dependence in each temperature range because of its structure.

That is, (i) at a temperature exceeding the glass transition temperature of the A block, the polymer as a whole is in a completely melted and softened state and exhibits plastic flowability. Therefore, the block copolymer can be easily processed, injection-molded and extruded by various general-purpose plastic processing machines. (Ii) In the temperature range below the glass transition temperature of the A block and above the crystal melting point of the B block, the block copolymer has a phase separation structure. B
The blocks remain in the melted rubber phase, and the A blocks become resinous and act as cross-linking points to network the polymer chains of the rubber phase. Therefore, in this temperature range, the polymer exhibits a crosslinked rubber-like property as a whole, and the strain is not relaxed by the added value and is substantially completely retained. (Iii) At a temperature equal to or lower than the melting point of the B block, each block of the polymer will be crystallized or vitrified, and the polymer as a whole will show a cured resin property, and the strain will be frozen.

Therefore, the shape-memory resin molded product obtained by the present invention is obtained by adding the block copolymer having the above-mentioned specific structure to a temperature exceeding the glass transition temperature of the A block, preferably 20 ° C.
Molded into a desired shape at a higher temperature, the temperature is below the glass transition temperature of the A block, preferably below the glass transition temperature of the A block and at least 50% of the crystals of the B block at 25 ° C. melt, more preferably the crystal It can be manufactured by re-molding into a shape different from the above at a temperature at which 90% or more melts, and cooling to room temperature while maintaining the deformation. When the shape memory resin molded body thus obtained is heated again to a temperature at which most of the B block crystals are melted, the frozen strain is released and the shape is recovered.

In the method for manufacturing the shape-memory resin molded body of the present invention,
While it is generally preferred to use the above block copolymers alone, incomplete block copolymers that do not contain an ABA block structure in the polymer chain produced during block copolymer preparation, such as A It may be a polymer composed of only blocks or B blocks, or a mixture of AB or BAB type block copolymers.
However, even in this case, unless the block copolymer specified in the present invention is contained in an amount of at least 30% by weight, the shape memory performance intended by the present invention cannot be sufficiently exhibited.

Further, the block copolymer used in the present invention may contain a block or a functional group other than those specified in the present invention in the polymer chain within the range not impairing the object of the present invention. In some cases, the inclusion of these significantly improves the miscibility with other polymers and fillers.

Further, depending on the application, in order to improve the shape memory performance, softening temperature, rigidity, strength, impact resistance, moldability, etc. of the resin material, a mixture with another polymer may be preferable. However, even in this case, unless the above block copolymer is contained as a polymer component in an amount of at least 30% by weight, the desired effect of the present invention cannot be sufficiently exhibited.

Particularly preferable examples of the polymer that can be mixed are a polymer containing an aromatic nucleus having a glass transition temperature of 100 ° C or higher and 25 ° C to 2 ° C.
A crystalline polymer having a melting point in the range of 00 ° C. may be mentioned. As a specific example, a styrene polymer as the former,
α-methylstyrene polymer, styrene-α-methylstyrene copolymer, other various alkyl-substituted styrene polymers, styrene-diphenylethylene copolymer, polyphenylene ethers, styrene-butadiene copolymer,
The copolymer of styrene and isoprene can be mentioned.
Specific examples of the latter include ethylene polymers, various α-olefin polymers, ethylene-propylene copolymers, transisoprene polymers, transbutadiene polymers, various polyamide resins, and various polyester resins. .

Furthermore, in addition to the above-mentioned polymer components, an inorganic filler or a plasticizer can be blended if necessary 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 1 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 include bentonite. Use of an inorganic filler in excess of 100 parts by weight undesirably reduces the shape memory performance and impact resistance of the obtained shape memory resin molded product.

The amount of plasticizer used is usually in the range of 1 to 20 parts by weight per 100 parts by weight of the polymer component. Examples of plasticizers are dibutyl phthalate, di- (2-ethylhexyl) phthalate, di- (2-ethylhexyl) adipate, diethylene glycol dibenzoate, butyl stearate, butyl epoxy stearate, tri- (2-ethylhexyl).
A phosphate etc. are mentioned.

The shape of the molded article of the present invention can be variously changed depending on its use and is not particularly specified. Further, it can be used for all applications in which the shape memory performance, which is a feature of the present shape memory resin molded product, can be exhibited. Examples of specific applications include toys, irregular pipe jointing materials, pipe internal laminating materials, lining materials, fastening pins, medical equipment such as kibs, stationery teaching materials, artificial flowers, dolls, computer dot printer rolls. Internal laminates, soundproofing agents, automobile bumpers, etc. that require deformation recovery after shock absorption, partition dividers for residential use, folding containers when not in use, and portable containers used to restore their shape when used. , Mechanical devices such as couplings, various heat-shrinkable tubes, and the like.

[Effects of the Invention] As described in detail above, according to the present invention, it is easy to process with a general-purpose plastic processing machine, has excellent shape memory characteristics (the shape recovery rate is high, and natural recovery of the shape hardly occurs), and It has become possible to easily manufacture a shape-memory molded article having a feature of being excellent in resin performance such as strength, heat resistance and weather resistance.

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

First, the method for producing the polymer used will be described.

(1) The polymers of Examples 1 to 3 were prepared by an anionic polymerization method with butyllithium using cyclohexane as a solvent to obtain α
-Polymerization of mixed monomer of -methylstyrene and styrene, 1,3-butadiene and again mixed monomer of α-methylstyrene and styrene, and hydrogenation reaction is performed on unsaturated bond of olefin part of the obtained polymer. Therefore, A-
A linear block copolymer corresponding to the B-A structure was obtained.

(2) The polymer of Comparative Example 1 is the same as Example 1 except that a mixed solvent of cyclohexane and tetrahydrofuran is used as the solvent.
~ 3 to obtain a non-crystalline linear block copolymer corresponding to the A-B-A structure.

(3) The polymer of Comparative Example 2 was prepared in the same manner as in Examples 1 to 3 except that the polymerization order of the monomers was 1,3-butadiene, a mixed monomer of α-methylstyrene and styrene, and 1,3-butadiene. , A linear block copolymer corresponding to the B-A-B structure was obtained.

(4) The polymer of Example 4 was prepared by sequentially polymerizing a mixed monomer of α-methylstyrene and styrene and 1,3-butadiene by anionic polymerization with butyllithium using cyclohexane as a solvent, followed by terminal coupling reaction with diphenyl carbonate. Then, the unsaturated bond of the olefin part of the obtained polymer was subjected to a hydrogenation reaction to obtain a star block copolymer corresponding to the (AB ₃ X structure).

(5) The polymer of Example 5 was obtained by polymerizing a mixed monomer of styrene and butadiene by an anionic polymerization method with butyllithium using cyclohexane as a solvent, and then polymerizing a mixed monomer of styrene and butadiene again. B-A having a tapered copolymer structure by performing a hydrogen addition reaction on the unsaturated bond of the olefin part of
A linear block copolymer corresponding to the -BA structure was obtained.

(6) The polymer of Example 6 was prepared by using cyclohexane as a solvent, a polystyrene-based macromer having an aromatic vinyl group at one end of the polymer chain, 2% by weight of isoprene, and 98% by weight.
Of 1,3-Butadiene-containing conjugated diene-based mixed monomer by anionic polymerization with butyllithium using barium-di-tert-butoxide as a cocatalyst, and hydrogenation reaction of unsaturated bond of olefin part of the obtained polymer. By doing A graft type block copolymer having a structure of (average n = 2.5) was obtained. The results of analysis of the structure and properties of the block polymer obtained above are shown in Table-1. Table 2 shows the evaluation results of the melt flowability of the polymer, the injection moldability, and the basic resin performance of the injection molded sheet.

Further, Table 2 also shows extremely excellent shape memory performance of the shape memory resin molded product obtained by remolding the obtained injection-molded sheet by uniaxially stretching.

Analysis and measurement conditions (a) The weight content of the block copolymer having the target structure and its molecular weight were determined by peak processing of GPC measurement data.

(B) The weight fraction of the A block was determined by processing the infrared spectrophotometer measurement data of the polymer before hydrogenation.

(C) The weight average molecules of A block and B block are
It was determined from GPC measurement data and polymer composition data.

(D) The glass transition temperature, crystallinity and crystal melting temperature were determined by a differential thermal analyzer.

(E) The 1,2-bond content of the butadiene part was determined by processing the infrared spectrophotometer data of the polymer before hydrogenation.

(F) The hydrogenation rate was analyzed by proton NMR.

Polymer evaluation conditions (a) Melt index was measured under G condition of ASTM D 1238-57T.

(B) Hardness was measured by Shore Durometer D at 25 ° C. according to ASTM D 1484-59T.

(C) The breaking strength and the breaking elongation are obtained by punching a sheet-shaped compact with an injection molding machine at a set temperature of 230 ° C and a mold temperature of 40 ° C.
According to JIS K-7113, it was measured with a No. 2 type test piece and a pulling speed G.

(D) The shape memory rate is 100 mm at 97 ° C. for a sheet-shaped molded body obtained by injection molding under the same conditions as above with a thickness of 2 mm and a width of 5 mm.
% (2-fold length), and the shape was fixed by immediately cooling it to room temperature with cold water to obtain a shape-memory resin molded product. Next, the shape-memory resin molded body thus obtained was heated with hot water at 97 ° C. for 2 minutes to recover the shape, and the ratio of the shrinkage width (recovery width) to the stretched width was measured and defined as the shape-memory rate.

(E) The injection moldability was judged based on the surface condition and dimensional stability of the sheet-shaped molded product which was punched at the injection molding machine set temperature of 230 ° C and the mold temperature of 40 ° C.

Claims (5)

[Claims] 1. A block copolymer having a weight average molecular weight in the range of 10,000 to 1,000,000, which contains an ABA block structure consisting of at least the polymer blocks A and B specified below in the polymer chain, A method for producing a shape-memory resin molded product, which comprises molding into a desired shape at a temperature exceeding the glass transition temperature of a block, and then remolding into a shape different from the above shape at a temperature lower than the glass transition temperature of A block. Here, the A block is a homopolymer of a vinyl aromatic compound,
A copolymer of a vinyl aromatic compound and another vinyl aromatic compound, a copolymer of a vinyl aromatic compound and a conjugated diene compound, or a hydrogenated product thereof, which has a glass transition temperature of 50 ° C or higher. This is a characteristic block. The A blocks may have the same structure or different structures. The B block is composed of a homopolymer of a conjugated diene compound, a copolymer of a conjugated diene compound and another conjugated diene compound, or a copolymer of a conjugated diene compound and a vinyl aromatic compound, and an unsaturated bond of the conjugated diene unit. Of which 50% by mole or more is a hydrogenated product, the degree of crystallinity at 25 ° C. is 5% by weight or more of the B polymer block, and at least 50% by weight of the crystals melt below the glass transition temperature of the A block. It is a polymer block characterized by being 2. A molded product molded into a desired shape is produced at a temperature below the glass transition temperature of the A block and at the B block.
The method for producing a shape-memory resin molded body according to claim 1, wherein the shape-memory resin molded body is reshaped into a shape different from the above shape in a temperature range in which at least 50% by weight of the crystals melt at 25 ° C. 3. The block copolymer has a chain block structure represented by the general formula (a) (AB) _n A (b) B (AB) _n A or (c) B (AB) _n AB. The method for producing a shape-memory resin molded body according to claim 1 or 2. Here, n is an integer of 1 or more and 10 or less, and each A block and each B block are as described above, and they may have the same structure or different structures. 4. A block copolymer having the general formula (d) [(AB) _n ] _m X (e) [(AB) _n A] _m X (f) [B (AB) _n ] _m X or ( g) The method for producing a shape-memory resin molded product according to claim 1 or 2, which has a star block structure represented by [B (AB) _n A] _m X. Here, n is an integer of 1 or more and 10 or less, m is 2 or more,
Is an integer of 10 or less, X is a terminal coupling agent,
Each A block and each B block are as described above, and may have the same structure or different structures. 5. A block copolymer having the general formula 3. The method for producing a shape-memory resin molded product according to claim 1, which has a graft type block structure represented by: Here, n is an integer of 1 or more and 10 or less, and each A block and each B block are as described above and may have the same structure or different structures.