JPH06313089A - Polymer composition - Google Patents

Abstract

PURPOSE:To obtain a polymer composition capable of giving molded products of low water absorptivity and good transparency and heat resistance, comprising an aromatic polycarbonate and a copolymer made up of methyl methacrylate unit, furylalkyl acrylate unit and comonomer unit. CONSTITUTION:This polymer composition capable of giving molded products of good transparency and heat resistance, low water absorptivity and excellent mechanical properties, comprises (A) a methyl methacrylate copolymer made up of (1)50-98wt.% of methyl methacrylate unit, (2)2-50wt.% of a monomer unit of the formula [R<1> is H or methyl; X is (substituted)furyl, dihydrofuryl or tetrahydrofuryl; (n) is 1 or 2] (e.g. furfuryl methacrylate) and (3)0-25wt.% of another alpha, beta-unsaturated monomer (e.g. phenyl methacrylate and (B) an aromatic polycarbonate.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to polymer compositions.
Specifically, it has excellent transparency and heat resistance and low water absorption,
The present invention relates to a polymer composition comprising a methyl methacrylate copolymer and an aromatic polycarbonate having an excellent balance of physical properties, and the polymer composition of the present invention has various properties such as a film, a sheet, a plate, and others due to its excellent properties. It is used as a molded product and can be effectively used in various optical fields such as lenses and optical disk substrates, and in optoelectronic fields.

[0002]

2. Description of the Related Art Polymethylmethacrylate has excellent properties such as transparency, weather resistance and surface hardness. But,
Since this resin has insufficient heat resistance and mechanical properties and has a high water absorption rate, it may not be suitable for use depending on the application, and its improvement is required. On the other hand, an aromatic polycarbonate, particularly a polycarbonate produced from bisphenol A, has excellent mechanical properties such as impact resistance, heat resistance and transparency, but has poor weather resistance and surface hardness and is There are problems such as a residual strain and a large orientation refractive index of a molded product obtained due to poor fluidity.

Therefore, in order to obtain a transparent resin having both the excellent characteristics of polymethylmethacrylate and the excellent characteristics of aromatic polycarbonate, it is conceivable to mix both resins. In that case, when polymethyl methacrylate and an aromatic polycarbonate (in particular, a polycarbonate of bisphenol A) are mixed in tetrahydrofuran, which is a common solvent for both, to form a cast film, a transparent complete compatibilizer is produced. However, when both resins are simply melt-mixed without using a solvent such as tetrahydrofuran, the cloud point of the mixture is as low as about 180 ° C, so mixing at a temperature of 180 ° C or higher causes separation into two phases. To do. Therefore, when a mixture of poly (methyl methacrylate) and an aromatic polycarbonate is melt-kneaded at a high temperature of 180 ° C. or higher necessary for melting the aromatic polycarbonate, a complete compatibilized product cannot be obtained and the pearls are phase-separated. It is known to result in a glossy, opaque composition [J. Polym. Sci., Polym. Phys. Ed. , 25 ,
1459 (1987)].

In order to improve the compatibility of a mixture of a methyl methacrylate polymer and an aromatic polycarbonate at high temperature, use of a methyl methacrylate copolymer having various comonomers introduced therein as the methyl methacrylate polymer. Is proposed. For example, JP-A-63-905
No. 51 discloses that a copolymer of methyl methacrylate and methacrylamide is melt-kneaded with a polycarbonate of bisphenol A to form a transparent composition, and JP-A-63-256647 discloses methyl methacrylate. It is described to melt-knead a copolymer of a maleimide such as N-cyclohexylmaleimide with a polycarbonate of bisphenol A to form a transparent or slightly hazy composition. However, according to these methods, since the comonomer to be copolymerized with methyl methacrylate contains a nitrogen atom, JP-A-63-256647.
As described in the examples of Japanese Patent Publication, when a composition of a methyl methacrylate copolymer and an aromatic polycarbonate is melt-molded, coloring is likely to occur, and the cloud point of the composition is also satisfactory. It has the drawback of not being expensive.

Then, in order to improve the above-mentioned drawbacks of the prior art using a methyl methacrylate copolymer having a nitrogen-containing comonomer unit, JP-A-64-1749 discloses that a carbocyclic group is contained in an ester group. It has been proposed to use a methyl methacrylate copolymer containing a (meth) acrylate unit and, if necessary, a monomer unit such as styrene. Such a methyl methacrylate copolymer and bisphenol A Polycarbonates are described as being mixed-extruded to give clear compositions which have a higher cloud point than compositions of methyl methacrylate homopolymer and bisphenol A polycarbonate.

However, the above-mentioned Japanese Patent Laid-Open No. 64-1749.
The cloud point of the polymer composition described in Japanese Patent Application Publication No. JP-A No. 2003-242242 is not sufficiently high, and the transparency is not satisfactory. That is, aromatic polycarbonate has a higher melt viscosity than a homopolymer or copolymer of methyl methacrylate, and a melt viscosity of a polymer composition comprising an aromatic polycarbonate and a methyl methacrylate homopolymer or copolymer. Will inevitably increase. Therefore, in order to reduce the melt viscosity of such a polymer composition and improve the moldability, it is necessary to perform the melt kneading or melt molding at a high temperature at which the viscosity of the composition decreases to an appropriate value. However, when such a high temperature is used, there is a problem that the polymer composition becomes cloudy and a transparent molded article cannot be obtained. Further, in a molded article obtained from a composition of a methyl methacrylate-based polymer and an aromatic polycarbonate, not only transparency but also heat resistance, low water absorption, high mechanical strength, etc. are required. In the case of the prior art, those other physical properties have not been sufficiently satisfactory.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to produce a molded article having a cloud point sufficiently higher than the temperature required for molding and having excellent transparency, and having a high heat resistance. A polymer composition comprising a methyl methacrylate-based polymer and an aromatic polycarbonate, which is good, has low water absorption, and is capable of obtaining a molded article having good balanced and excellent physical properties. Is to provide. A further object of the present invention is to provide a polymer composition of a methyl methacrylate polymer and an aromatic polycarbonate, which can easily produce a molded article having the above-mentioned excellent properties by ordinary melt molding or the like. That is.

[0008]

Means for Solving the Problems As a result of repeated studies by the present inventors to solve the above problems, the methyl methacrylate polymer mixed with an aromatic polycarbonate has a furan ring or a hydrogenated furan ring. The present invention has been completed by finding that the above object can be achieved by using a methyl methacrylate copolymer obtained by copolymerizing at least one of acrylic acid ester and methacrylic acid ester.

That is, the present invention provides (A) (a) a methyl methacrylate unit of 50 to 98% by weight, (b) the following general formula (I);

[0010]

[Chemical 2] (Wherein R ¹ is a hydrogen atom or a methyl group, X is a furyl group substituted or unsubstituted by an alkyl group, a dihydrofuryl group or a tetrahydrofuryl group, and n is 1 or 2) 2 to 50% by weight of monomer units, and (c) 0 to 25 other α, β-unsaturated monomer units
A polymer composition comprising a methyl methacrylate copolymer in an amount of 1% by weight; and (B) an aromatic polycarbonate.

The methyl methacrylate copolymer (A) used in the present invention must contain 50 to 98% by weight of a methyl methacrylate unit, preferably 50 to 98%.
The content is 95% by weight, more preferably 50 to 98% by weight. When the content of methyl methacrylate in the methyl methacrylate copolymer (A) is less than 50% by weight, good weather resistance and transparency cannot be maintained, while 98
If the content exceeds 10% by weight, the compatibility with the aromatic polycarbonate decreases, and it becomes impossible to obtain a composition having a sufficiently high cloud point when mixed with the aromatic polycarbonate.

Further, a methyl methacrylate copolymer (A)
The group X in the monomer unit represented by the above general formula (I) in the general formula (I) is generally the following formula;

[0013]

[Chemical 3] Is a furyl group, a dihydrofuryl group or a tetrahydrofuryl group represented by the formula, wherein: represents a furyl group, and represents a dihydrofuryl group, and represents a tetrahydrofuryl group.

In the present invention, in the furyl group, dihydrofuryl group or tetrahydrofuryl group represented by the above formulas, one or two hydrogen atoms bonded to a furan ring, a dihydrofuran ring or a tetrahydrofuran ring.
One or more of them may be optionally substituted with an alkyl group, and thus all of the ring-bonded atoms are hydrogen atoms, some of the ring-bonded hydrogen atoms are substituted with an alkyl group, or ring-bonded hydrogen atoms. The case where all of the above are substituted with an alkyl group is included. When two or more of the ring-bonded hydrogen atoms are substituted with an alkyl group, those alkyl groups may be the same or different from each other. As the alkyl group, an alkyl group having 1 to 4 carbon atoms is preferable, and a methyl group is particularly preferable. Further, in the monomer represented by the general formula (I), n is 1 or 2
And a monomer in which n is 1 is particularly preferable.

Without limitation, general formula (I)
Examples of the monomer represented by are furfuryl methacrylate, furfuryl acrylate, dihydrofurfuryl methacrylate, dihydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, tetrahydrofurfuryl acrylate, furylethyl methacrylate, furylethyl acrylate, dihydrofuryl. Examples thereof include ethyl methacrylate, dihydrofurylethyl acrylate, tetrahydrofurylethyl methacrylate, tetrahydrofurylethyl acrylate, and the methacrylates or acrylates in which the furyl group is substituted with 1 to 4 methyl groups. The methyl methacrylate copolymer (A) used in the present invention may be a copolymer of only one type of the monomer units represented by the general formula (I), or two types. The above may be copolymerized.

In the present invention, the proportion of the monomer unit represented by the general formula (I) in the methyl methacrylate copolymer (A) is required to be 2 to 50% by weight,
5 to 50% by weight is preferable, and 10 to 50% by weight is more preferable. The ratio of the monomer unit represented by the general formula (I) is 2
When it is less than 50% by weight, sufficient compatibility with the aromatic polycarbonate cannot be obtained. On the other hand, when it exceeds 50% by weight, the strength of the methyl methacrylate copolymer (A) decreases, and when it is mixed with the aromatic polycarbonate. The strength of the composition is also low.

Further, a methyl methacrylate copolymer (A)
May be 25 to the extent that the effects of the present invention are not impaired.
It may contain up to wt% of other α, β-unsaturated monomer units. Examples of the monomer capable of forming another α, β-unsaturated monomer unit include styrene, α-styrene,
Aromatic vinyl monomers such as vinyltoluene, 2,4-dimethylstyrene, and halogen-substituted styrene; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate , 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, and the like (meth) acrylic acid esters having 1 to 18 carbon atoms; (meth) acrylic acid, ( (Meth) acrylamide,
(Meth) acrylonitrile, maleic anhydride, maleic imide, monomethyl maleate, monoethyl maleate, monoisopropyl maleate, dimethyl maleate, diethyl maleate and the like can be mentioned. Of these, styrene and α-styrene are preferable as the aromatic vinyl monomers, and those having 1 to 12 carbon atoms are preferable as the (meth) acrylic acid ester.

In the present invention, the molecular weight of the methyl methacrylate copolymer (A) is not particularly limited, but from the viewpoint of strength characteristics and meltability, the number average molecular weight is 10,000 to 5,000.
50,000, preferably 50,000 to 50
Those of 10,000 are more preferably used.

The methyl methacrylate copolymer (A) is
It can be produced by a known method of producing a polymer by polymerizing an α, β-unsaturated monomer compound, and particularly by radical polymerization. When radical polymerization is carried out, for example, bulk polymerization, solution polymerization, suspension polymerization or emulsion polymerization can be adopted. As the radical polymerization initiator at that time, for example, asobisisobutyronitrile, azo compounds such as azobis (γ-dimethylvaleronitrile), benzoyl peroxide, cumyl peroxide, oxyneodecanoate, diisopropyl peroxydicarbonate, t-butyl cumyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, cyclohexanone peroxide,
Mention may be made of peroxy compounds such as methyl ethyl ketone peroxide, dicumyl peroxide, lauroyl peroxide and the like. Usually, a polymerization initiator is added in an amount of 0.05 to 0.5% by weight with respect to the total amount of monomer components, and polymerization is performed at a temperature of 50 to 140 ° C. for 2 to 20 hours to give a methyl methacrylate copolymer ( A) can be obtained.

Further, a methyl methacrylate copolymer (A)
It is convenient to use a chain transfer agent to control the molecular weight of the. Examples of the chain transfer agent include methyl mercaptan, ethyl mercaptan, isopropyl mercaptan, n-butyl mercaptan, t-butyl mercaptan, n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, ethylthioglycolate, mercaptoethanol, thiol. -Β-naphthol,
Thiophenol and the like can be mentioned, and the chain transfer agent is generally 0.05 to 0.5 with respect to the total amount of the monomer components.
It is preferable to use it in the range of% by weight.

As the aromatic polycarbonate (B) used in the present invention, any of aromatic polycarbonates can be used, but preferred examples include 4,4-dihydroxydiphenylalkane-based polycarbonates, and particularly, Polycarbonates obtained from bisphenol A are preferred. The molecular weight of the aromatic polycarbonate (B) is not particularly limited, but from the viewpoint of meltability, the number average molecular weight is preferably 10,000 to 500,000, and more preferably 10,000 to 60,000. .

In the polymer composition of the present invention, the methyl methacrylate copolymer (A) and the aromatic polycarbonate (B) are used.
It is compatible in all mixing ratio ranges with and is transparent in the melt-kneaded state. However, if the amount of one polymer is too small, a polymer composition capable of producing a molded article in which all the above-mentioned properties such as transparency, moisture resistance, low water absorption, mechanical strength and the like are balanced is obtained. Therefore, the mixing ratio of the methyl methacrylate copolymer: aromatic polycarbonate (B) in the polymer composition is 1:99 by weight.
The ratio is preferably 99: 1, preferably 2:98 to 98: 2, more preferably 10:90 to 90:10.

The method for mixing the methyl methacrylate copolymer (A) and the aromatic polycarbonate (B) is not particularly limited, and a usual method can be adopted, for example, melting using a Brabender type mixer or the like. Can be mixed. Further, instead of melt-kneading the methyl methacrylate copolymer (A) and the aromatic polycarbonate (B),
The polymer composition may be produced by dissolving in a common solvent such as tetrahydrofuran and mixing, and casting the resulting solution into a film. Then, the polymer composition of the present invention can be put into any form such as pellets, chips, powders and the like. The polymer composition of the present invention may optionally contain additives such as antioxidants and ultraviolet absorbers which are usually used in this type of polymer, and the polymer composition of the present invention Other polymers may be contained within a range that does not impair the characteristics of 1.

The polymer composition of the present invention containing the methyl methacrylate copolymer (A) and the aromatic polycarbonate (B) can be molded by any method such as melt molding and solution molding, and particularly the cloud point. Since its compatibility and transparency are high even when it is melt-kneaded at high temperature, extrusion molding, injection molding,
Melt molding such as extrusion blow molding and injection blow molding can be smoothly performed, and cast molding and cast molding can also be performed. A wide variety of molded products such as films, sheets, plates, lenses, and optical parts such as optical disk substrates can be manufactured by such molding.

[0025]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In the following examples, “part” means “part by weight” and “%” means “% by weight”. Furthermore, each physical property value was measured by the following methods.

Number average molecular weight : measured by GPC (polystyrene conversion) using tetrahydrofuran as a solvent. Copolymer composition : JEOL-GSX270, CDCl
_It was determined from the ¹ H-NMR spectrum measured using ₃ as a solvent. Melt viscosity : The melt viscosity at a shear rate of 100 sec ^-1 at 280 ° C. was determined by using a flow tester (manufactured by Shimadzu Corporation). Cloud point : Tetrahydrofuran furan solution in which the polymer composition was dissolved was spread on a cover glass with a glass rod to form a solvent film, which was vacuum dried at 120 ° C. for 24 hours. The obtained thin film-like transparent polymer composition was allowed to stand at various temperatures, and the lower limit temperature at which it became cloudy when left at each temperature for 15 minutes or more was defined as a cloud point.

Light transmittance : Using a sample molded to a thickness of 2 mm by hot pressing, the total light transmittance was measured with an integrating sphere type haze meter. Water absorption rate : The press-molded test piece was placed in distilled water at 23 ° C., and the weight increase rate was measured when no weight increase due to water absorption was observed.

<< Synthesis Examples 1 to 3 >> Into a glass tube-like ampoule tube, methyl methacrylate (MMA) and the monomers for copolymerization shown in Table 1 below were introduced at a ratio shown in Table 1, and then introduced into the ampoule tube. Toluene (100 parts) and azoisobutyronitrile (0.1 part) as a polymerization initiator were added, and freeze-deaeration was repeated 5 times. The ampoule tube was placed in an oil bath whose temperature was raised to 60 ° C., and polymerization was carried out for 3 hours. After that, the ampoule tube was cooled, opened, and purified with an acetone-methanol mixed solvent three times, and the obtained polymer was dried under reduced pressure. The yield, copolymer composition and number average molecular weight (Mn) of the obtained polymer were as shown in Table 1.

<< Synthesis Example 4 >> Similar to Synthesis Examples 1 to 3, 70 parts of methyl methacrylate (MMA) and furfuryl methacrylate 2 were added to a glass tube-shaped ampoule tube.
0 parts and 10 parts of cyclohexyl methacrylate were introduced, and 120 parts of toluene and 1,1 as a polymerization initiator were introduced.
-Azobiscyclohexane-1-carbonitrile 0.1
After adding a part and repeating freeze-deaeration 5 times, the pressure in the ampoun tube was reduced and the mixture was sealed. The ampoule tube was put into an oil bath whose temperature was raised to 90 ° C., and polymerization was carried out for 2 hours. After that, the ampoule tube was cooled, opened, and purified with an acetone-methanol mixed solvent three times, and the obtained polymer was dried under reduced pressure. The yield, copolymer composition and number average molecular weight (Mn) of the obtained polymer were as shown in Table 1.

<Synthesis Example 5> In the same manner as in Synthesis Example 4, 93.3 parts of methyl methacrylate (MMA) and 6.7 parts of phenyl methacrylate were introduced into a glass tube-like ampoule tube, and toluene 100 was added thereto. Parts, 0.1 part of 1,1-azobiscyclohexane-1-carbonitrile as a polymerization initiator was added, and after freeze-deaeration was repeated 5 times, the ampoule tube was depressurized and sealed. The ampoule tube was put into an oil bath whose temperature was raised to 90 ° C., and polymerization was carried out for 2 hours. Then, cool the ampoule tube and open it.
The polymer was purified three times with a mixed solvent of methanol, and the obtained polymer was dried under reduced pressure. The yield, copolymer composition and number average molecular weight (Mn) of the obtained polymer were as shown in Table 1.

[0031]

[Table 1]

Examples 1 to 7 Each of the methyl methacrylate copolymers produced in the above Synthesis Examples 1 to 4 and an aromatic polycarbonate (polycarbonate of bisphenol A; number average molecular weight of 20,000) [Teijin Chemical ( stock)
[Panlite L-1250]] was mixed in the proportions shown in Table 2 below, and kneaded with a plastograph (manufactured by Brabender) at 250 ° C. at a stirring speed of 20 rpm for 10 minutes. The melt viscosity, cloud point, and heat transition temperature of the obtained polymer composition were as shown in Table 2. Further, the obtained polymer composition is press-molded at 250 ° C. to prepare a test piece,
When the light transmittance, birefringence and water absorption were measured,
The results are shown in Table 2 below.

Comparative Example 1 The methyl methacrylate copolymer prepared in the above Synthesis Example 5 and the same aromatic polycarbonate as used in Examples 1 to 4 were used as shown in Table 2 below: Mixing in a weight ratio of 50, Examples 1-7
Kneading was performed for 10 minutes at 235 ° C. and a stirring speed of 20 rpm in the same manner as in (1). The melt viscosity, cloud point, and heat transition temperature of the obtained polymer composition were as shown in Table 2. Further, the obtained polymer composition was press-molded at 230 ° C. to prepare a test piece, and its light transmittance, birefringence and water absorption were measured, and the results are shown in Table 2 below.

[0034]

[Table 2]

From the results shown in Table 2 above, the polymer compositions of the present invention of Examples 1 to 7 comprising methyl methacrylate copolymers containing furfuryl methacrylate or tetrahydrofurfuryl methacrylate as copolymerized units and aromatic polycarbonates. It can be seen that each of them has a high cloud point of 270 ° C. or higher, and has high light transmittance and excellent transparency. In Examples 1 to 7, the thermal transition temperature of the polymer composition was confirmed only at one point between the methyl methacrylate copolymer and the aromatic polycarbonate, and the thermal transition temperature was the composition ratio of the polymer composition. Since it changed in proportion to, it was proved that they were completely compatible systems. On the other hand, in the case of the polymer composition of Comparative Example 1 consisting of a methyl methacrylate copolymer containing phenyl methacrylate as a copolymerization unit and an aromatic polycarbonate, its cloud point was as low as 240 ° C. and its light transmittance was low. It can be seen that the transparency is poor.

[0036]

When molding is performed using the polymer composition of the present invention, the transparency and heat resistance are good, the water absorption is low, and the mechanical properties are good. It is possible to manufacture a molded product that has Since the polymer composition of the present invention has a sufficiently high cloud point that can be applied to melt molding, when the polymer composition of the present invention is used, phase separation and white turbidity are caused by ordinary melt molding. It is possible to easily produce a molded article having excellent transparency without causing

Claims (1)

[Claims] 1. (A) (a) Methyl methacrylate unit 50
˜98% by weight, (b) the following general formula (I); (Wherein R ¹ is a hydrogen atom or a methyl group, X is a furyl group substituted or unsubstituted by an alkyl group, a dihydrofuryl group or a tetrahydrofuryl group, and n is 1 or 2) 2 to 50% by weight of monomer units, and (c) 0 to 25 other α, β-unsaturated monomer units
A polymer composition comprising (B) an aromatic polycarbonate; and (B) an aromatic polycarbonate.