KR20040079118A - Transparent Polymethylemethacrylate/Polycarbonate Resin Composition - Google Patents

Abstract

PURPOSE: A transparent poly(methyl methacrylate)/polycarbonate resin composition is provided to allow a poly(methyl methacrylate)/polycarbonate blend to be obtained by extrusion process only without additional polymerization process irrespective of the kind of polycarbonate. CONSTITUTION: The poly(methyl methacrylate)/polycarbonate resin composition comprises: 100 parts by weight of a resin component comprising 1-99 wt% of a poly(alkyl methacrylate) resin or a poly(alkyl acrylate) resin, and 1-99 wt% of a polycarbonate resin or a polyester carbonate resin; and optionally 0.00001-5 parts by weight of additives for reducing the molecular weight of the resin. Preferably the additives comprise a basic compound containing an alkali metal and alkaline earth metal; an amine compound or ammonium compound; and at least one compound selected from Lewis acids.

Description

Transparent polymethyl methacrylate / polycarbonate resin composition

The present invention relates to a transparent polymethylmethacrylate / polycarbonate resin composition. More specifically, polymethyl methacrylate resin and polycarbonate resin having an appropriate range of molecular weight are selected or polymethyl methacrylate / poly is adjusted to an appropriate level of molecular weight by using an additive capable of adjusting the molecular weight of polycarbonate. A transparent polymethylmethacrylate / polycarbonate resin composition for preparing a carbonate blend is disclosed.

Polymethyl methacrylate (hereinafter referred to as 'PMMA') resin is not only excellent in transparency and weather resistance, but also excellent in mechanical strength such as tensile strength and modulus of elasticity, surface gloss, adhesiveness, and so on. It is widely used for building materials, adhesives, and other plastic modifiers. However, the impact resistance is inferior to other plastic materials, and has a disadvantage that it is relatively easily broken by an external impact, thereby increasing the product thickness or using it for a limited use.

Polycarbonate (hereinafter referred to as 'PC') resin is an engineering plastic that has excellent impact resistance at room temperature and low temperature, and is excellent in transparency, thermal stability, self-extinguishing, dimensional stability, and is widely used in electric and electronic products and automobile parts. It is used instead of glass in areas where transparency and impact resistance are required, such as windows. Compared to glass, PC is easy to process into a desired shape and has a lighter weight and superior impact resistance, but has a disadvantage of being very scratch resistant.

In order to supplement the weak impact resistance of PMMA resin, research has been conducted to introduce an elastomer rubber having excellent impact resistance to PMMA. In general, when the rubber is introduced into the PMMA resin, the impact resistance may be improved to a satisfactory level, but a problem of deterioration of transparency, which is the biggest advantage of the PMMA, occurs.

Japanese Patent Publication No. 46-11035, US Patent Registration No. 4,287,315 and US Patent Registration No. 3,646,164, Progress in Colloid Polymer Science 90: 227-231 (1992) and Italian Patent Registration No. 47,946 A89 In order to give impact resistance to PMMA, impact-resistant PMMA was prepared using elastomer rubber. However, the PMMA produced by the conventional method is greatly improved in terms of impact resistance, but has a disadvantage in that it is very inferior in transparency.

In the case of using an elastomer rubber, it is generally known that transparency remains due to the size of the dispersed phase and the difference in refractive index between the dispersed phase and the continuous phase resin. That is, if the size of the dispersed phase resin is much smaller than the wavelength of visible light, light scattering hardly occurs even though the refractive index does not coincide with the resin, and transparency is maintained. Also, when the dispersed phase and the continuous phase have the same refractive index, the dispersed phase particles form an optically uniform phase. Although large, transparency is maintained.

However, it is not easy to uniformly disperse the rubber particles having a size such that light scattering, which is generally known to have a diameter of 100 nm or less, in the PMMA resin is not easy, and thus the degree of impact resistance improvement is insignificant. It has been described in US Patent No. 5,338,804 that the impact resistance is hardly improved when using particles having a diameter of 100 nm or less, and the improvement is very small even if the impact resistance is improved.

In addition, since PMMA resins that form continuous phases are mixed with other acrylate monomers or additives to improve thermal stability, the refractive indices vary slightly depending on the type of product. It is also not easy to make. In this regard, it is described in US Patent No. 5,338,804 that the transparency is lowered if the refractive index difference of the two phase resins is 0.005 or more.

In addition, even if the refractive index of the elastomer rubber is similar to that of PMMA, since the degree of change of the refractive index of each resin constituting the dispersed phase and the continuous phase is different, even if the refractive index is matched at a specific temperature such as room temperature, high transparency can be obtained. Transparency is often reduced at other temperatures, ie high temperatures above room temperature or low temperatures below room temperature.

Ethylene-based copolymer rubber, poly-elastic rubber, which is disclosed in Japanese Patent Publication No. 46-11035, US Patent Registration No. 4,287,315, and Italian Patent No. 47,946 A89, and which is already known in other documents. Butadiene, butadiene / alkyl acrylate copolymer, acrylate rubber and the like shows a significant change in refractive index with temperature changes. As an example, when ethylene / vinyl acetate copolymer rubber is used as the impact resistant agent of PMMA, the impact resistance of PMMA is improved and transparent at room temperature, but the transparency changes rapidly with temperature change. In another example, the impact resistance is also increased by using an elastomeric rubber component having a core / shell structure of styrene / butyl acrylate / methyl methacrylate having a refractive index similar to that of PMMA. On the other hand, the transparency at room temperature is excellent, but has a slight blue light, and also has the disadvantage that the transparency of PMMA greatly decreases when the temperature rises.

On the other hand, the method of coating the surface was mainly carried out to improve the scratch resistance of the PC. For example, United States Patent Registration Nos. 3,451,838, 3,986,997 and 4,027,073, etc., are coated with organic polysiloxane on the surface of the PC to increase scratch resistance, and a method of using an adhesive to increase the adhesion between the siloxane and the PC. US Patent Registration Nos. 3,707,397 and 4,242,383. In addition, a method of increasing scratch resistance through a method of coating an acrylic hard coat on a surface is known.

In addition to these surface coating techniques, attempts to increase the scratch resistance of common resins include attempts to increase surface hardness by adding nucleating agents, lubricants or inorganic materials to polypropylene (polymer engineering and science 41, 23-31). (2001), and attempts to increase scratch resistance by adding polyamide to thermoplastic polyolefins (2002 Antec technical paper, L. Saggese et al.) Are known, but these methods are difficult to apply in the case of transparent resin PC. .

Therefore, it is expected to improve the impact resistance of the PMMA and the scratch resistance of the PC when the transparent and high surface strength PMMA having low impact resistance and the PC which is transparent and high impact resistance but low scratch resistance are mixed. .

However, PMMA / PC blends prepared by melt processing have been disclosed in Japanese Patent Registration No. 68-13384, in which a pearlescent very opaque blend is formed. This is because the refractive indices of PMMA and PC are significantly different as 1.489 and 1.585, respectively, and phase separation occurs because the two resins are not compatible.

In order to prepare a transparent blend by increasing the compatibility of the two resins, an attempt to make a transparent blend with PC is made by making a PMMA copolymer compatible with PC or by preparing a copolymer containing syndiotactic-PMMA. And attempts to make transparent blends using fluorinated polycarbonate copolymers.

For example, in US Pat. No. 6,359,069, a copolymer containing about 80 to 90% PMMA was mixed at a ratio of 90/10 with a PC to make a transparent blend, and US Pat. Nos. 5,338,798 and 5,280,070 In prepared a copolymer containing more than 60% syndiotactic PMMA to prepare a transparent blend with PC. In addition, US Pat. No. 5,292,809 prepared PMMA and transparent blend rolls using polycarbonate containing 15% or more of bisphenol substituted with fluorine. All of these attempts raise the problem of having to go through a number of processes by preparing specific copolymers and by preparing transparent blends of these copolymers with other resins.

As a method of producing a transparent PMMA / PC blend using a single polymer rather than a blend with such a copolymer, a small amount of additive is added to the blend of PMMA and PC so that a reaction occurs between the two resins to prepare a transparent blend. US Patent Registration No. 6,103,827. However, in this patent, the PC used in the preparation of the transparent blend has a hydroxyl end group of 5% or more, and most commercially produced PCs without the hydroxyl end group have a problem of not being transparent.

In order to solve the above problems, the present invention, by using a PC and PMMA having a suitable molecular weight or a small amount of additives according to the blending ratio of the blend by controlling the molecular weight of the PC produced as a commercial product using a transparent PMMA It is an object to provide a / PC resin composition.

The above and other objects of the present invention can be achieved by the present invention described below.

The present invention to achieve the above object, (A) 1 to 99 parts by weight of polyalkyl methacrylate or polyalkyl acrylate resin; And (B) 99 to 1 parts by weight of polycarbonate (PC) resin or polyester carbonate; provides a transparent polymethyl methacrylate / polycarbonate resin composition comprising a.

The polymethyl methacrylate / polycarbonate resin composition may further include 0.00001 to 5 parts by weight of an additive for reducing the molecular weight of the (A) or the (B) resin, based on 100 parts by weight of the mixture of (A) and (B). Can be.

A basic compound in which the additive includes an alkali metal and an alkaline earth metal; Amine or ammonium compounds; And it can be selected from the group consisting of one or more mixtures selected from Lewis acids.

Said (A) resin is a homopolymer having methyl methacrylate as a main component; A copolymer comprising at least one of an alkyl acrylate group and an alkyl methacrylate group; A resin in which a functional group capable of reacting with the compatibilizer and the polycarbonate is substituted with the homopolymer or copolymer resin; And mixtures of one or more thereof.

Linear and branched aromatic polycarbonate (PC) homopolymers wherein (B) the resin is prepared by reacting dihydroxy phenol with phosgene or by reaction of dihydroxy phenol with a carbonate precursor; Polyester copolymers; Or a mixture of one or more of these.

When the weight average molecular weight of the resin (B) is greater than the weight part of the resin (B) and the weight average molecular weight of the resin (A) is 50,000 or more, 5,000 to 40,000 may be used.

The weight average molecular weight of the said (A) polymethyl methacrylate resin has a weight part of the said (B) polycarbonate resin more than the weight part of the said (A) polymethyl methacrylate resin, and the weight of the said (B) polycarbonate resin When the average molecular weight is 30,000 or more, it may be 5,000 to 60,000.

Hereinafter, the present invention will be described in detail.

The present inventors have found that a transparent blend can be made by selecting PC and PMMA having an appropriate level of molecular weight depending on the blend ratio of the blend. In addition, the present inventors have found that the use of a small amount of additives can control the molecular weight of the PC being produced as a commercial product, and that the transparent PMMA / PC blend can be prepared using the same.

The PMMA resin used in the present invention includes a homopolymer containing methyl methacrylate as a main component and a copolymer containing at least one of an alkyl acrylate group or an alkyl methacrylate group or a mixture of one or more thereof.

PC resins used in the present invention are commonly used aromatic polycarbonate resins, which are linear and branched PC homopolymers prepared by reacting dihydroxy phenol with phosgene or by reaction of dihydroxy phenol with a carbonate precursor. And polyester copolymers or mixtures of one or more thereof. The dihydroxy phenol is 2,2-bis (4-hydroxyphenyl) propane (ie bisphenol A), bis (4-hydroxy phenyl) methane, 2,2-bis (4-hydroxy-3,5 -Dimethylphenyl) propane and 1,1-bis (4-hydroxyphenyl) cyclohexane and the like, and the carbonate precursors include diphenyl carbonate, carbonyl halide, diaryl carbonate and the like.

The additive used in the present invention is a substance capable of reducing the molecular weight of the PC, and a basic compound containing an alkali metal or an alkaline earth metal, an amine or an ammonium compound, and a Lewis acid may be used.

Blends prepared in the present invention may be mixed with additives such as ultraviolet absorbers, heat stabilizers, antioxidants, flame retardants, lubricants, pigments and / or dyes according to their respective applications.

The manufacturing method of the transparent blend using the PMMA and PC is as follows.

When polymerizing or selecting PMMA or PC with appropriate molecular weight, transparent blends can be prepared by melt-blending processing, and when it is not possible to obtain a resin with appropriate molecular weight, the molecular weight of each resin is controlled by using additives or processing conditions. A transparent blend can be prepared by this. For example, an additive capable of reducing the molecular weight of a PC may be added to the PMMA / PC blend, or may be mixed with the PC to adjust the molecular weight of the PC and then mixed with the PMMA to prepare a transparent blend. More specifically, for example, at least one 0.1 part by weight of the additive containing metal ions such as aluminum stearate, magnesium stearate, calcium stearate, calcium stearate, etc. Put together in a melt mixer to get a clear PMMA / PC blend.

The amount of additive added here should be controlled according to the molecular weight and mixing ratio of PMMA and PC to be mixed. In other words, the higher the molecular weight of the initial PC, the lower the molecular weight to the molecular weight level that can have compatibility, the amount of additives must be increased. The lower the molecular weight of the PMMA, the higher the molecular weight level of the PC can have compatibility. A small amount of additives may be added. In addition, as the mixing ratio of PC to PMMA increases, the amount of additives must increase. However, when more additives are added than necessary, the mechanical properties tend to be lowered. In the case of adjusting the molecular weight of PMMA, a transparent blend may be prepared by adding an additive which may break the chain or by using PMMA having an appropriate molecular weight from the beginning.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the examples, and a PMMA / PC blend is prepared through molecular weight control and PMMA is improved by using such a technique. Or include a comprehensive statement on the direction of the approach to making a PC with improved scratch resistance.

EXAMPLE

Specifications of PMMA, PC resin and additives used in the following Examples and Comparative Examples are as follows. PMMA used IG840 (LG MMA) having a weight average molecular weight of about 90,000 and PC used LEXAN 141 (GE plastics) having a weight average molecular weight of about 50,000 was prepared by mixing according to the composition of Table 1 below.

Polymethyl methacrylate (PMMA) (parts by weight) Polycarbonate (PC) (part by weight) Additive (part by weight) Example One 80 20 MgSt: 0.2 2 70 30 MgSt: 0.3 3 80 20 CaSt: 0.2 Comparative example One 100 0 - 2 80 20 - 3 0 100 -

Example 1

40 g of PMMA, 10 g of PC and 0.1 g of magnesium stearate (MgSt) were simultaneously added to a melt mixer (Haake Rheomix 540) and mixed for 10 minutes.

Example 2

35 g of PMMA, 15 g of PC, and 0.15 g of magnesium stearate were placed in a melt mixer at the same time and mixed for 10 minutes.

Example 3

The same procedure as in Example 1 was carried out except that 0.1 g of calcium stearate was added instead of magnesium stearate.

Comparative Example 1

Comparative Example 1 was prepared by adding only 100 parts by weight of PMMA resin.

Comparative Example 2

The same procedure as in Example 1 was conducted except that no magnesium stearate was added.

Comparative Example 3

Comparative Example 3 was prepared by adding only 100 parts by weight of a PC resin (trade name: LEXAN 141).

[Test Example]

Samples having a weight average molecular weight and a thickness of 3.2 mm were prepared by the injection molding method for Examples 1 to 3 and Comparative Examples 1 to 3, and the visible light transmittance was measured using a spectrophotometer, and the results are shown in Table 2 below. It was.

Visible light transmittance (%) Weight average molecular weight (PC) Example One 86.1 26,000 2 81.8 26,000 3 46.2 35,000 Comparative example One 89.9 - 2 0.04 53,000 3 88.0 53,000

As shown in Table 2, a small amount of additives were added to the PC produced as a commercial product to make a transparent PMMA / PC blend. In particular, a transparent blend was prepared using a commercial PC (trade name: LEXAN 141) without hydroxy at the end group, which means that the transparency of the present invention is not caused by the reaction between the two resins by the catalyst, but rather by the catalyst control. This is an example showing that it is caused by.

As described above, the present invention provides a transparent PMMA / PC blend through the extrusion process without any polymerization process, by controlling the molecular weight of PMMA and PC regardless of the type of PC (does not have a hydroxyl group at the end of the chain). There is an advantage.

While the invention has been described in detail above with reference to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope and spirit of the invention, and such modifications and variations fall within the scope of the appended claims. It is also natural.

Claims (7)

(A) 1 to 99 parts by weight of a polyalkyl methacrylate or polyalkyl acrylate resin; And, (B) 99 to 1 parts by weight of polycarbonate (PC) resin or polyester carbonate; Transparent polymethyl methacrylate / polycarbonate resin composition comprising a. The method of claim 1, The polymethylmethacrylate / polycarbonate resin composition may further include 0.00001 to 5 parts by weight of an additive for reducing the molecular weight of the resin (A) or (B), based on 100 parts by weight of the mixture of (A) and (B). Transparent polymethyl methacrylate / polycarbonate resin composition, characterized in that. The method of claim 2, A basic compound in which the additive includes an alkali metal and an alkaline earth metal; Amine or ammonium compounds; And A transparent polymethylmethacrylate / polycarbonate resin composition, characterized in that it is selected from the group consisting of one or more mixtures selected from Lewis acids. The method of claim 1, Said (A) resin is a homopolymer having methyl methacrylate as a main component; A copolymer comprising at least one of an alkyl acrylate group and an alkyl methacrylate group; A resin in which a functional group capable of reacting with the compatibilizer and the polycarbonate is substituted with the homopolymer or copolymer resin; And A transparent polymethylmethacrylate / polycarbonate resin composition, characterized in that it is selected from the group consisting of one or more of these mixtures. The method of claim 1, Linear and branched aromatic polycarbonate (PC) homopolymers wherein (B) the resin is prepared by reacting dihydroxy phenol with phosgene or by reaction of dihydroxy phenol with a carbonate precursor; Polyester copolymers; Or a mixture of at least one of these. A transparent polymethyl methacrylate / polycarbonate resin composition. The method of claim 1, The weight average molecular weight of the resin (B) is 5,000 to 40,000 when the weight part of the resin (A) is greater than the weight part of the resin (B) and the weight average molecular weight of the resin (A) is 50,000 or more. Transparent polymethyl methacrylate / polycarbonate resin composition. The method of claim 1, The weight average molecular weight of the said (A) polymethyl methacrylate resin has a weight part of the said (B) polycarbonate resin more than the weight part of the said (A) polymethyl methacrylate resin, and the weight of the said (B) polycarbonate resin When the average molecular weight is 30,000 or more, the transparent polymethyl methacrylate / polycarbonate resin composition, characterized in that 5,000 to 60,000.