JPH0222354A - Shape memory resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition improved in processability by blending a norbornene based polymer with a specific crystalline polymer. CONSTITUTION:The aimed composition obtained by blending 100 pts. wt. norbornene based polymer having >=10 deg.C glass transition temperature and >=1000000 number-average molecular weight with 3-100 pts.wt. crystalline polymer having <=200 deg.C crystal melting point exceeding glass transition temperature of norbornene based polymer, >=10% crystallinity at ordinary temperature, <0 deg.C glass transition temperature and 500-200000 number-average molecular weight. The crystalline polymer is a homopolymer of conjugated diene being >=80% in 1,4-trans content of the conjugated diene part or copolymer of a conjugated diene and other conjugated diene or conjugated diene and vinyl aromatic compound. The conjugated diene is 1,3-butadiene.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a norbornene-based shape memory resin composition with improved processability by mixing a specific crystalline polymer with a norbornene-based polymer.

[Prior art and its problems Molded articles of conorbornene polymers, especially norbornene polymers with a glass transition temperature of 10°C or higher and a number average molecular weight of 1 million or higher, are deformed at a temperature below the molding temperature, and then It is known that when a polymer is cooled below its glass transition temperature, its deformation can be fixed, and when it is heated above its glass transition temperature, it recovers to its original shape (Japanese Patent Laid-Open No. 59-5
3528).

Norbornene polymers generally have a glass transition temperature of approximately -2
It is a polymer in the range of 0 to 100°C. Among these, polymers whose glass transition temperature exceeds room temperature are considered to be used alone or with the addition of a small amount of plasticizer for use as plastics. However, because this type of polymer usually has an extremely large molecular weight, it has poor fluidity even at the glass transition temperature.
Compression molding is generally used as a molding means, and it has been difficult to use mass-produced molding methods such as injection molding and transfer molding.

In addition, even in compression molding, norbornene-based polymers with shape memory properties are resin-like powders with a bulk specific gravity of 0.25 to 0.35 at room temperature, so air bubbles may be mixed into the molded product, and flow may occur. There is a problem in that workability and moldability are poor due to defects and the like.

In addition, norbornene polymers have excellent miscibility with various oils, so blending a large amount of oil can lower the glass transition temperature and viscosity, giving it the same processability as natural rubber or ordinary synthetic rubber. You can also do it. However, although such measures can improve processability, a problem arises in that the properties as a shape memory resin, which is the object of the present invention, are significantly deteriorated.

On the other hand, by mixing a resin with a low glass transition temperature that is in resin form at room temperature, the glass transition temperature of the composition can be maintained above room temperature and the viscosity during processing can be lowered, thereby improving shape memory properties. A method of retaining and improving workability is also known (see JP-A-63-54460).

However, even with this method, when processing at temperatures above the glass transition temperature by mixing a large amount of resin with a low glass transition temperature,
Stress relaxation of strain, which is the driving force for shape recovery of the molded object, becomes more likely to occur, resulting in a decline in shape memory properties, and on the other hand, a sufficient processability improvement effect cannot be expected even when a small amount of resin with a low glass transition temperature is mixed. There was a problem.

[Means for Solving the Problems] As a result of repeated studies to improve the processability of norbornene-based polymers, the present inventors found that by mixing a specific crystalline polymer with norbornene-based polymers, The present invention was achieved by discovering that processability can be improved without significantly reducing shape memory properties.

That is, the present invention has a crystal melting point exceeding the glass transition temperature of the norbornene polymer and 200° C. or less, for 100 parts by weight of a norbornene polymer having a glass transition temperature of 10° C. or more and a number average molecular weight of 1 million or more. and a crystalline polymer having a crystallinity of 10% or more at room temperature, a glass transition temperature of less than 0°C, and a number average molecular weight in the range of 500 to 200,000 3 to 1
The object of the present invention is to provide a norbornene-based shape memory resin composition having improved processability, which is made by mixing 00 Jutabe.

A molded article obtained using the shape memory resin composition of the present invention is deformed at a temperature lower than its molding temperature, and then cooled to a temperature lower than the glass transition temperature of the composition to fix the deformation. It has the ability to satisfactorily recover its original shape by heating to a temperature above the transition temperature and below the crystal melting point of the crystalline polymer.

That is, when the composition of the present invention is processed, the crystalline polymer acts as a plasticizer at a temperature higher than the melting point of the crystalline polymer, which is designed to exceed the glass transition temperature of the norbornene-based polymer. The product will have excellent workability. On the other hand, at temperatures below the melting point of the crystalline polymer at which shape memory performance is exhibited, the crystalline polymer undergoes phase separation as a crystalline phase, and the shape memory properties of the composition are not adversely affected by the plasticizing effect. .

The norbornene polymer used in the shape memory resin composition of the present invention has a glass transition temperature of 10°C or higher, preferably 20°C or higher, more preferably 30°C to 60°C, and a number average molecular weight of 1 million That's all. When the glass transition temperature is less than 10° C. and the number average molecular weight is less than 1 million, the excellent shape memory performance aimed at by the present invention cannot be sufficiently achieved.

The norbornene polymer used in the present invention is a ring-opening polymer or copolymer of bicyclo(2,2,1)hebutene-2 or a derivative thereof. Specific examples of the constituent monomers include alkyl-5-bicyclo(2,2,1) such as bicyclo(2,2,1)hebutene-2, methyl-5-bicyclo(2,2,1)hebutene-2, etc. ,1) Hebutene-2 monomer, methoxy-5-bicyclo(2,2,1)hebutene-
2, Ethoxy-5-bicyclo(2,2,1)hebutene-
Alkoxy-5-bicyclo(2,2,1)butene-2, bicyclo(2,2,1)butene-2-5-carboxylic acid ester, bicyclo(2,2,1) Examples include diester polymers of hebutene-2-5,8 dicarboxylic acid and mixtures thereof.

A typical polymer is a norbornene polymer which is a ring-opening polymer of bicyclo(2,2,1)hebutene-2.

The crystalline polymer used in the present invention has a temperature exceeding the glass transition temperature of the norbornene polymer constituting the composition, and has a temperature of 200°C.
A crystalline melting point of the following, preferably a crystalline melting point exceeding the glass transition temperature of the norbornene polymer by 10°C or more and 180°C or less, more preferably a crystalline melting point exceeding the glass transition temperature of the norbornene polymer by 20°C or more and 150°C or less. melting point, its single crystallinity at room temperature is 10% or more, preferably 20% or more, more preferably 30% or more, its glass transition temperature is less than 0°C, and its number average molecular weight is 500 to 20%. 10,000, preferably 1,000 to 100,000,
More preferably, it is selected from various polymers in the range of 5,000 to 50,000.

If the crystalline melting point of the crystalline polymer is lower than the glass transition temperature of the norbornene polymer, phase separation of the crystals will not proceed sufficiently and the shape memory properties of the composition will significantly deteriorate, which is undesirable.

If the crystalline melting point of the crystalline polymer exceeds 200° C., it is necessary to increase the processing temperature of the composition, which is undesirable because the processability decreases. Moreover, if the crystallinity at room temperature is less than 105, phase separation will not proceed sufficiently and the shape memory properties of the composition will deteriorate, which is not preferable. Furthermore, if the glass transition temperature of the crystalline polymer is 0° C. or higher, the crystal growth rate will be significantly reduced, which is unfavorable for processing. When the molecular weight of the crystalline polymer is less than 500, the mixability of the composition decreases,
If it is more than 200,000, the processability of the composition during processing will be significantly reduced, which is not preferable.

Preferred examples of the crystalline polymer include trans-butadiene polymer, trans-butadiene styrene block copolymer, syndio-1,2-butadiene polymer, trans-isoprene polymer, and ε-caprolactone polymer. . The most preferred crystalline polymer is trans-butadiene polymer. Further, the crystalline polymer may be a homopolymer or a copolymer.

These crystalline polymers may be used alone or in combination of two or more and mixed with the norbornene polymer.

The composition ratio of the polymer components of the shape memory resin composition of the present invention is 3 to 100 polymer parts, preferably 5 to 80 polymer parts, and more preferably 10 polymer parts to 100 polymer parts of the norbornene polymer. ~50 weights. If the composition ratio of the crystalline polymer is less than 3 parts by weight, the effect of improving processability is not sufficient, and if it exceeds 100 parts by weight, processability is greatly improved, but shape memory performance is also significantly reduced.

In the shape memory resin composition of the present invention, in addition to the above-mentioned polymer components, inorganic fillers and plasticizers can be blended in order to adjust hardness, plasticity, etc. Further, stabilizers, pigments, etc., which are general additives added to polymer resin materials, can be appropriately added in the case of the present invention as well as in conventional resin materials.

The amount of the inorganic filler used is usually in the range of 2 to 100 parts by weight, preferably 5 to 30 parts by weight, per 100 parts by weight of the polymer component. Examples of inorganic fillers include titanium oxide,
Examples include calcium carbonate, clay, talc, mica, bentonite, silica, and carbon. The use of more than 100 parts by weight of an inorganic filler is undesirable because it significantly reduces the impact strength and shape memory properties of the resulting resin composition.

The amount of plasticizer used usually ranges from 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-
Examples include ethylhexyl) phosphate, various petroleum oils, and the like.

The shape memory resin composition of the present invention can be used in an extruder, a kneader,
It can be easily mixed using a roll or the like. Alternatively, they can be dissolved in a suitable solvent and mixed in the solution.

The shape memory resin composition obtained in this way has the following characteristics: excellent shape memory properties, physical properties such as rigidity, strength, and impact resistance, and mass production processing such as injection moldability and extrusion moldability. It can be used for various resin materials by taking advantage of its ability to

For example, (1) medical right-hand fixation materials such as splints and casts, and various protector materials for sports, taking advantage of the relatively low temperature, which means that they can be easily processed or partially corrected by touching the human skin or by hand; 2) A heat-sensitive shrink film or laminate (laminate film) that has been extruded into a sheet shape and then subjected to cold stretching or hot stretching, (3)
) Heat-sensitive shrinkable sleeves, coupling devices or bundles of electric wires, insulating tubes, which are formed into cylindrical or various shapes by injection molding or extrusion molding, and then cold-stretched to expand them; (4) Temporary at low temperatures; Automobile bumpers, toys, dolls, artificial flowers, or heat-sensitive sensors using them, which take advantage of the shape memory property of recovering the shape from the deformed shape to the original injection molded or compression molded shape when a certain temperature is reached. (5) After memorizing the rough shape in advance through molding, it takes advantage of the characteristics that it is easy to fit to the mold surface by heat shrinkage or shape recovery, and it is easy to heat or modify details by touching the human body. Can be used for various shaping materials and head shaping materials for wigs, etc.

[Effects of the Invention] As explained in detail above, the present invention provides various excellent physical properties of norbornene-based polymers as resins, such as excellent properties in stiffness, strength, impact resistance, and excellent shape memory properties. The object of the present invention is to provide a shape-memory resin composition that maintains the properties of the shape-memory resin composition and has improved moldability and processability.

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

Examples 1 to 4 Norbornene polymers listed in Table 1 and trans-butadiene polymers or ε-caprolactone polymers were mixed at 3.5
The mixture was kneaded at 150°C using an inch oven roll.

The resulting composition was molded at a molding temperature of 160°C and a molding pressure of 150k.
A sheet-like molded product with a thickness of 2 mrn was obtained by compression molding at g/cJ for 5 minutes.

Thereafter, this molded product was left in an air oven at 50°C for 5 minutes, and then stretched 100% with a stretching holder.
It was left in an air oven at 0°C for 15 minutes. Thereafter, it was left to cool at room temperature for 5 minutes, and when removed from the holder, the shape was fixed in the stretched state. Furthermore, this product was immersed again in hot water at 50° C. for 5 minutes, and the shape recovery performance was evaluated using the characteristic value of permanent deformation.

The results obtained are shown in Table 1.

From this result, it was found that the shape memory resin composition according to the present invention
It is clear that the norbornene polymer has significantly improved processability without substantially impairing the shape memory performance of the norbornene polymer.

(Margins below) Part 1 Table Notes (1) N0RSOREX manufactured by CdF, France Glass transition temperature 35°C, molecular weight 2 million or more 2 (2) 1.
4- Trans-bonded gold rate 91%, molecule ff 119,000
Butadiene polymer with melting point of 98°C and glass transition temperature of -90°C (3) Placel H-1 manufactured by Daicel Chemical Industries, melting point of 60°C,
ε-caprolactone polymer with a glass transition temperature of -60°C and a molecular weight of 10,000 Open roll processability 1: Does not wrap around an open roll.

2: It does not wrap around an open roll, but becomes a sheet.

3: It wraps around an open roll and becomes a sheet, but it is bagged.

4: Wrap around an open roll to form a sheet.

5: It wraps around an open roll and becomes a sheet, and the bank also rotates well.

Claims (1)

[Claims] 1. For 100 parts by weight of a norbornene polymer having a glass transition temperature of 10°C or more and a number average molecular weight of 1 million or more,
It has a crystal melting point below and a crystallinity of 10% at room temperature.
or more, the glass transition temperature is less than 0°C, the number average molecular weight is 50
A norbornene-based shape memory resin composition having improved processability and comprising 3 to 100 parts by weight of a crystalline polymer in a range of 0 to 200,000 parts by weight. 2. The crystalline polymer is a conjugated diene homopolymer with a 1,4-trans content of 80% or more in the conjugated diene part, a copolymer of a conjugated diene and another conjugated diene, or a copolymer of a conjugated diene and a vinyl aromatic compound. The shape memory resin composition according to claim 1, which is a copolymer. 3. The shape memory resin composition according to claim 2, wherein the conjugated diene is 1,3-butadiene.