JPH01236209A - Novel copolymer and shape memory resin - Google Patents

Abstract

PURPOSE:To obtain a copolymer good in workability and shape recovery performance, by using a block or random copolymer component which has specific units and prescribed number-average molecular weight and isotacticity. CONSTITUTION:The present block or random copolymer has two or more units represented by the given formula and a number-average molecular weight of 10,000 or more and an isotacticity of 50% or above. In the formula, R is 1-10C alkyl, 6-20C aryl or 7-20C aralkyl. In view of the mechanical properties, etc., a block or random copolymer which has as the constituent units equivalent amounts of polymethyl methacrylate units and ester units of a 2-10C alkyl group of polymethyl methacrylate is most preferred. Also, by varying the molar ratio of both components to thereby vary the second-order transition point, a block or random copolymer having various processabilities and a good balance among physical properties can be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION Co-Industrial Applications The present invention relates to novel block or random copolymers. More specifically, the present invention relates to a block or random copolymer having rubber elasticity near room temperature and having excellent toughness such as impact resistance and flexibility.

The present invention also relates to a shape memory resin that maintains a state of being deformed into an arbitrary shape near room temperature and recovers (restores) the memorized original shape when the temperature rises above room temperature. .

Further, the copolymer of the present invention is useful as a dental material.

[Conventional technology and its problems]

Hitherto, block or random copolymers having structural units such as those of the present invention have not been known, and in particular, it has not been known at all that a polymer having such a structure has the characteristics of a shape memory elastomer.

When it is difficult to attach, assemble, or transport a molded article of a polymer compound, it is difficult to attach, assemble, or transport the shaped article. To restore the specified shape by heating operation etc. after completion of assembly, etc., and to make it function as intended.
In addition, various studies have been made in the past regarding materials suitable for uses where the main purpose is to restore a deformed molded body to its original state, that is, shape memory resins or shape memory molded bodies.

Conventionally, shape-memory resins or shape-memory molded bodies have been developed, for example, norbornene-based polymer molded bodies (Japanese Unexamined Patent Application Publication No. 1983-1999-1).
53528), a crosslinked molded product using polycaprolactone (JP-A-59-11315) or trans-1,4
- Cross-linked molded product using polyisoprene JP-A-62-1
92440), but they all have advantages and disadvantages, such as poor workability or poor shape recovery performance.

The present inventors have completed the present invention as a result of extensive studies to solve the problems of the conventional art.

[Means for solving problems]

The present invention provides a block or random copolymer comprising two or more units represented by the following general formula (1), having a number average molecular weight of 10.000 or more and an isotacticity of 50% or more.

H3 -C-CH2-(1) DOR However, in the formula, R is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms.

The present invention also provides a shape-recoverable copolymer composed of a block or random copolymer having a number average molecular weight of 10.000 or more and an intactness of 50% or more, which is composed of two or more types of units shown in maximum (1) above. The present invention provides a shape memory resin with excellent performance.

In the present invention, R in general formula (1) is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 200 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and an alkyl group having 1 to 10 carbon atoms. Examples of groups include straight-chain alkyl groups such as methinobeethinopepropinopebutinopepentynobehexyl, heptyl, octyl, nonyl and decyl, and branched alkyl groups such as isopropyl, isobutyl and t-butyl. and alicyclic alkyl groups such as cyclohexyl. Next, examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a tolyl group, and a naphthyl group. Also, the number of carbon atoms is 7 or more.

The shape memory resin of the present invention is composed of a block or random copolymer having a number average molecular weight of 10.000 or more and an intactility of 50% or more, which is composed of two or more types of units shown in (1) above. It is what was done.

The isotactic content (isotacticity) of the copolymer of the present invention is 50% or more, preferably 80% or more, and more preferably 90% or more.

Block or random identification of the copolymers of the present invention is N
This can be determined by MR etc.

The block or random copolymer of the present invention has 2 or more carbon atoms.
Due to the presence of a chain of methacrylic acid esters having 10 alkyl groups or the like in the ester group, the secondary transition point thereof is generally low. In particular, when the secondary transition point is around room temperature, a molded product molded into a desired shape takes a long time to recover its shape after being deformed, and in fact remains deformed for a long time. However, it has a shape memory property that allows it to quickly return to its original shape when it is immersed in hot water or exposed to hot air to provide thermal energy.

The block or random copolymer and shape memory resin of the present invention preferably have a number average molecular weight in the range of 10.000 to about 1.000.000 from the viewpoint of moldability.

The copolymerization ratio of the copolymer of the present invention is at least 0.1 mol%,
Maximum 99.9 mol%, preferably minimum 1 mol%, maximum 9
9 mol%, more preferably a minimum of 10 mol%, a maximum of 90 mol%
Practically speaking, the ratio of each component of the copolymerization monomer component is 1 to 3, preferably 1 to 2 (the ratio is calculated using the larger one as the molecule).

For example, in the present invention, a block or random copolymer containing substantially equivalent amounts of a polymethyl methacrylate unit and an ester unit of an alkyl group having 2 to 10 carbon atoms in polymethacrylic acid is used as a constituent unit of a block or random copolymer. Copolymers are the most suitable from the viewpoint of mechanical properties, but by changing the molar ratio of both components, the secondary transition point can be changed, they can have various processability, and the balance of physical properties can be changed. Discrete block or random copolymers can be made.

The number of each unit in the copolymer or shape memory resin of the present invention can be freely selected within the above number average molecular weight range.

In addition, when the copolymer or shape memory resin of the present invention is composed of a block copolymer, if each structural unit represented by -maximum (1) is, for example, A, B, C..., then the block copolymer is As a polymer, AB.

-A-B-A, A-B=C, A-B-A-B, A-C-
Examples include B.

In the copolymer of the present invention, the type and number of R (2
By changing the proportion of each unit (eg, ternary, quaternary, etc.) and the proportion of each unit, the secondary transition point of the polymer can be changed, and it has various processability and a well-balanced physical property. Shape memory resin can be made.

As a method for producing the block copolymer of the present invention, for example, when methyl methacrylate is used as the first component of the copolymer, it may be produced by a known block copolymerization method from methyl methacrylate and an alkyl ester of methacrylic acid. In order to obtain a copolymer with high integrity as a polymerization initiator, an initiator consisting of a Grignard reagent, such as JP-A-61-1792, can be used as an anionic polymerization initiator.
Initiators such as those described in No. 10 can be effectively used. When such an initiator is used, a block copolymer can be effectively produced by adding, for example, ethyl methacrylate monomer to the active end of polymethyl methacrylate to the reaction system. isotacticity
A copolymer with excellent stereoregularity is obtained. In this way, the polymerization system that allows the polymerization reaction to proceed in a living manner is
It is effectively used in the synthesis of the block copolymer of the present invention.

Next, as a method for producing the random copolymer of the present invention, the most common method is to simultaneously charge two monomers from the beginning and add a polymerization initiator. For example, methyl methacrylate and ethyl acrylate are dissolved in toluene solvent,
By adding an anionic polymerization initiator such as t-butylmagnesium bromide, a random copolymer with high intectivity can be obtained.

The stereoregularity and random or block identity of the copolymer can be determined by NMR.

[For production]

The block or random copolymer or shape memory resin of the present invention may be used as a plasticizer, mold release agent, pigment, auxiliary agent, additive, lubricant, filler, flame retardant, etc., depending on the purpose of making a molded product. etc. can be added. Furthermore, in order to improve light resistance, oxidation resistance, etc., thermal decomposition inhibitors, antioxidants, ultraviolet absorbers, etc. may be added.

Furthermore, when a conductive filler is blended with the copolymer or shape memory resin of the present invention, a conductive shape memory resin can be obtained.

Examples of the conductive filler include conductive carbon black such as Ketchien black and acetylene black, and metal powder such as iron powder, nickel powder, and copper powder.

The amount of conductive filler to be blended may be such that the shape memory resin can be heated by supplying electricity and quickly restore its original shape.

Further, the shape memory resin of the present invention can further improve its performance by copolymerizing a copolymer with a moa/mer having a crosslinkable functional group in a side chain such as allyl methacrylate, and further crosslinking the copolymer. You can also do it.

The block or random copolymer of the present invention is transparent and can be thermoplastically processed to easily produce molded articles of any shape.

Therefore, the block or random copolymer of the present invention can be used as a film, fiber, or other molded product, and in particular can be used as a polymer having shape memory properties. Furthermore, it is also used as a dental material.

The shape memory resin of the present invention can be easily processed into any shape at room temperature and maintains that shape for a long time.

Moreover, by applying thermal energy, such as by soaking it in boiling water, it can be restored to its original shape. As described above, the conductive material is restored to its original shape by applying thermal energy by energization. The restoring temperature in this case needs to be higher than the glass transition temperature TG. Note that shape memory can be achieved by molding the resin at a temperature considerably higher than the glass transition temperature TG.

The shape memory resin of the present invention utilizes such characteristics to
Jointing materials for pipes of different diameters, internal laminate materials for pipes, laminate materials for rod-shaped objects, automobile bumpers, gap materials for residential partitions, stationery, teaching materials, parts for toys, decorative parts,
Tightening has a wide range of uses, such as fixing materials for work and construction such as pins, and dental materials.

〔Example〕

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

Example 1 70 g (0.70 mol) of methyl methacrylate and 350 ml of toluene were charged in a reaction vessel with a capacity of 1.5 β equipped with a stirrer under nitrogen, and after cooling to -60°C, t bromide was added.
- Ether solution of butylmagnenium 31mf (14m
mol) was added to start the polymerization reaction. 6 hours later -
80 g of ethyl methacrylate (0,70
mol) and 350 ml of toluene was added and the reaction was continued for an additional 12 hours. Then methanol 10
ml was added to stop the polymerization reaction, the reaction mixture was poured into hexane 7β, and the precipitate was collected by filtration and washing.
It was dried under reduced pressure at 0°C for 13 hours.

Yield was 146g.

The composition ratio of the block copolymer (confirmed to be a block copolymer by NMR) determined by proton NMR method is methyl methacrylate unit/ethyl methacrylate unit -
1,0/1.0, the average stereoregularity expressed in triplets is 96.6% for isotactic triplets, 1.9% for heterotactic triplets, and 1.5% for syndiotactic triplets. Met. The number average molecular weight determined by vapor pressure osmosis is 12.50.
0, Molecular weight dispersity determined by gel permeation chromatography method (!J w / !, I n )
was 1.29.

The glass transition temperature measured with a differential scanning calorimeter is 19.0℃
Met.

FIG. 1(A) shows the carbonyl carbon absorption in the 125', IH2' 3CN MR spectrum of the obtained isotactic block copolymer. (Measurement conditions: in deuterated chloroform, 55°C) 176.51 and 17
The peaks at 6 and 37 ppm are XiMA chain and E
This is due to isotactic triads of MA chains, indicating that all chains are highly isotactic. The composition determined from these absorption intensities is MMA/EMA
=1.0/1.0.

A transparent sheet made by hot pressing the obtained block copolymer is immersed in hot water, deformed into a specific shape such as a spiral, and slowly cooled to room temperature. It can be transformed into different shapes. When immersed in hot water again, it quickly restores its original specific shape, and shape description 1
．． Sound l! It has the properties of an IT resin (shape memory elastomer) and can be used for shape memory articles.

Example 2 50 g of methyl methacrylate was prepared in the same manner as in Example 1.
(0.50 mol), 250 g of toluene and 5.0 mmol of t-butylmagnesium bromide at -60°C.
The polymerization reaction was carried out for 2 hours, and 10% of ethyl methacrylate was added to this.
A mixture of 3 g (0.90 mol) and 500 ml of toluene was added, and the reaction was continued for an additional 36 hours. After the polymerization was terminated, the reaction mixture was poured into 7.5 ρ of hexane, and the block polymer was recovered in the same manner as in Example 1. Yield was 134g.

The obtained copolymer was confirmed to be a block copolymer by NMR.

The composition ratio of the copolymer is methyl methacrylate unit/ethyl methacrylate unit -1/1.57, and the stereoregularity is 95.4% isotactic triad and 2 heterotactic diad.
．． 9% and syndiotactic triads 1.7%.

The number average molecular weight determined by vapor pressure osmosis method was 26.900, and the molecular weight dispersity (Mw/~In) determined by gel vermutation chromatography method was 2.11. The glass transition temperature measured with a differential scanning calorimeter was 9.7°C.

A transparent sheet made by hot pressing the obtained block copolymer is immersed in hot water, deformed into a specific shape such as a spiral, and slowly cooled to room temperature. It can be transformed into different shapes. When immersed in hot water again, it quickly recovers its original specific shape, develops the properties of a shape memory resin (shape memory elastomer), and can be used in shape memory article applications.

Example 3 3.09 m+n of catalyst t-butylmagnesium bromide was added to 460 toluene solvents in which 463 mmol of methyl methacrylate and 453 mmol of ethyl methacrylate were dissolved.
ol was added thereto, and the mixture was reacted at -60°C for 45 hours. After stopping the reaction with a small amount of methanol, the n-
Hexane was added to precipitate the polymer.

A random copolymer was obtained with a yield of 93.4%, a secondary transition point of 28.3°C, and a number average molecular weight (osmotic pressure method) of IL 30.
It was 0. According to proton Nl and IR, methyl methacrylate in the copolymer was 50 [Tl01%. Stereoregularity is 95.5% isotactic triad, 3.4% heterotactic diad, 1 syndiotactic triad.
．． It was 1%.

FIG. 1(B) shows the carbonyl carbon absorption of the resulting interftin random copolymer similar to that in FIG. 1(A). As shown in the figure, the absorption of 176,5 to 176,7 ppw is due to monomer chain triads containing an MMA unit in the center (EM A - MM A - EMA, EMA
- MM
A-EMA-MMA, MMA EM
This is due to the isotactic chain of A EMA etc.). In the diagram, for example, "rEME" is EMA-MMA-EM.
Indicates absorption by A chain. The composition determined from the absorption intensity of these peak groups is MMA/EMA=1.0/
It was 1.0.

A transparent sheet made by hot pressing the obtained random copolymer is immersed in hot water, deformed into a specific shape such as a spiral, and slowly cooled to room temperature. It can be transformed into different shapes. When immersed in hot water again, it quickly recovers its original specific shape, has the properties of a shape memory resin (shape memory elastomer), and can be used in shape memory article applications.

[Brief explanation of the drawing]

Figure 1 (A) and (B) show the respective NMs of the block copolymer (A) and random copolymer (B) obtained in the example.
It is a figure showing an R spectrum. Applicant's agent Kaoru Furuya

Claims (1)

[Scope of Claims] 1. A block or random copolymer comprising two or more units represented by the following general formula (1), having a number average molecular weight of 10,000 or more and an isotacticity of 50% or more. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) However, in the formula, R is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. . 2. A shape memory resin having shape recovery performance, which is composed of the copolymer according to claim 1.