KR100583064B1 - Transparent polycarbonate / polyester resin composition with improved impact strength and chemical resistance - Google Patents

Abstract

The present invention relates to a polycarbonate / polyester resin composition having transparency and excellent impact strength and having improved chemical resistance to an organic solvent, and more specifically, (A) 5 to 90% by weight of an aromatic polycarbonate resin, (B The present invention relates to a thermoplastic resin composition comprising 5 to 90% by weight of a polyester carbonate copolymer and 5 to 90% by weight of a (C) copolyester resin.

Polycarbonate, polyester carbonate, copolyester, impact strength, transparency, chemical resistance

Description

Transparent polycarbonate / polyester resin composition with improved impact strength and chemical resistance

The present invention relates to a polycarbonate / polyester resin composition having transparency and excellent impact strength and improved chemical resistance to an organic solvent, and more specifically, to a polycarbonate resin, a polyester carbonate copolymer, and a copolyester resin. Regarding the resin composition, the resin composition of the present invention may provide a resin and a molded article exhibiting excellent impact strength while maintaining the transparency inherent in polycarbonate and improved chemical resistance to organic solvents.

Representative polycarbonate resin is a general-purpose thermoplastic engineering plastic manufactured by polycondensation of bisphenol A and phosgene and has a glass transition temperature of about 150 ° C. It is an excellent heat-resistant engineering plastic that replaces glass and is used for housing of electrical and electronic products, or for building and advertising plates. The physical properties of such polycarbonate resins originate from phenyl groups and carboxyl groups, and molecular structural properties such as rigidity of the molecular chain and binding of rotation affect the physical properties.

However, polycarbonate resins have limited chemical resistance and require caution when used for contact with organic solvents, certain detergents, strong alkalis, certain fatty acids, oils and greases.

Conventionally, efforts have been made to blend polycarbonates with other thermoplastic resins to improve the physical properties of polycarbonates. For example, US Pat. No. 3,218,372 discloses resin compositions in which polycarbonate and polyalkylene terephthalate are mixed to lower melt viscosity and improve ductility than polyalkylene terephthalate. However, this method has a problem in that the compatibility between the two resins is poor and opaque and the impact strength is lowered. In addition, US Pat. No. 4,391,954 discloses resin compositions consisting of copolyesters consisting essentially of repeating units derived from a mixture of polycarbonate and isophthalic acid, terephthalic acid and 1,4-cyclohexanedimethanol. The method does not provide sufficient impact strength. U.S. Patent No. 4,634,737 discloses a copolyester and olefin acrylate copolymer consisting of isophthalic acid, terephthalic acid, ethylene glycol and 1,4-cyclohexanedimethanol, with copolymerized polycarbonates having 25 to 90 mole percent ester bond Although compositions are disclosed, such compositions become opaque and do not obtain sufficient impact strength. US Pat. No. 4,188,314 discloses sheet moldings having improved chemical resistance, including copolyesters derived from polycarbonate and isophthalic acid, terephthalic acid and 1,4-cyclohexanedimethanol. Not enough impact strength can be obtained.

The present invention has been made to solve the above problems, the technical problem to be achieved by the present invention is that the transparency or impact strength is significantly lowered when mixing the polycarbonate with other types of resins incompatible with the polycarbonate To solve the problem.

Accordingly, it is an object of the present invention to provide a resin composition in which a polyester carbonate copolymer and a copolyester resin are mixed with a polycarbonate resin to improve chemical resistance to an organic solvent while maintaining transparency and impact resistance, which are inherent in polycarbonate. It is.

The present invention relates to a polycarbonate / polyester resin composition, and more particularly, 5 to 90% by weight of (A) aromatic polycarbonate resin, 5 to 90% by weight of (B) polyester carbonate copolymer, and (C) nose The present invention relates to a thermoplastic resin composition containing 5 to 90 wt% of a polyester resin, and to a thermoplastic resin composition having excellent impact strength and chemical resistance to an organic solvent while maintaining transparency that has been difficult to achieve in the prior art.

Referring to the present invention in more detail as follows.

According to the present invention, when the polyester carbonate copolymerized with aliphatic dibasic acid is mixed in the polycarbonate / copolyester resin composition, excellent impact strength is maintained while maintaining transparency. Since polyester carbonate has ester group and carbonate group in main chain, compatibility of polycarbonate and copolyester is improved. In addition, since the polyester resin is contained, chemical resistance to organic solvents, which is a disadvantage of polycarbonate, is greatly improved. As a result, the resin composition which consists of a polycarbonate, polyester carbonate, and copolyester resin can provide the resin composition and molded article excellent in transparency, impact resistance, and chemical resistance.

According to the components of the polycarbonate / polyester resin composition according to the present invention described above in more detail as follows.

(A) aromatic polycarbonate (hereinafter 'PC')

Thermoplastic aromatic PC resins can be prepared by polymerizing a dihydric phenol monomer and a carbonate precursor monomer in the presence of a molecular weight modifier to control the molecular weight.

The dihydric phenols may be any substance derived from the structure of Formula 1 below.

Wherein X is a straight, branched or cyclic aliphatic alkylene having no functional group, or is a straight, branched or cyclic containing functional group such as sulfide, ether, sulfoxide, sulfone, phenyl, naphthyl and isobutylphenyl Aliphatic alkylene, preferably straight, branched or cyclic alkylene containing 1 to 10 carbons;

R ₁ and R ₂ represent a halogen atom, a straight, branched or cyclic alkyl group;

n and m independently represent the integer of 0-4.

Examples of the dihydric phenols include bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) naphthylmethane and bis (4-hydroxyphenyl). )-(4-isobutylphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1-ethyl-1,1-bis (4-hydroxyphenyl) propane, 1-phenyl-1,1 -Bis (4-hydroxyphenyl) ethane, 1-naphthyl-1,1-bis (4-hydroxyphenyl) ethane, 1,2-bis (4-hydroxyphenyl) ethane, 1,10-bis ( 4-hydroxyphenyl) decane, 2-methyl-1,1-bis (4-hydroxyphenyl) propane, or 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) and the like But not representative of these are bisphenol A described above.

The carbonate precursor is another monomer of the PC resin, including but not limited to, for example, carbonyl chloride, carbonyl bromide, bis halo formate, diphenyl carbonate or dimethyl carbonate, and the like, and phosgene (carbonyl chloride). Is preferably used.

As the molecular weight modifier, a monofunctional compound similar to a known material, that is, a monomer used in PC production, may be used. Such monofunctional materials are based on, for example, phenols such as para-isopropylphenol, para-t-butylphenol, para-cumylphenol, para-isooctylphenol, and para-isononylphenol. Derivatives or aliphatic alcohols may be used, but is not limited thereto. Among them, para-t-butylphenol (PTBP) is most preferably used.

On the other hand, it is preferable that the aromatic PC resin which can be used for this invention uses the thing whose viscosity average molecular weights (Mv) measured in the methylene chloride solution are 17,000-40,000, and it is more preferable to use 20,000-30,000 things. When the average molecular weight is less than 17,000, mechanical properties such as impact strength and tensile strength are significantly lowered. When the average molecular weight is more than 40,000, there is a problem in processing of the resin due to an increase in melt viscosity.

In addition, the aromatic PC resin usable in the present invention may use one or more PC resins including monomers of the above-mentioned dihydric phenols and carbonate precursors, preferably linear polycarbonate resins, branched polycarbonate resins and cyclic polycarbonates. One or more resins selected from the group consisting of carbonate resins can be used.

The aromatic PC resin as described above that can be used in the present invention may be used 5 to 90% by weight, preferably 10 to 70% by weight relative to the total resin composition. If the aromatic PC resin is less than 5% by weight can not exhibit the inherent physical properties of the PC resin, such as impact resistance, if more than 90% by weight has a disadvantage of poor chemical resistance.

(B) Polyester carbonate copolymer ('PEC' below the polyester-carbonate copolymer)

A process for the production of PEC is disclosed in US Pat. No. 3,169,121, whereby a portion can be prepared by introducing long-chain aliphatic ester derivatives into the chain instead of the divalent phenols, which are hard parts, which are currently commercially available. Is being produced.

PEC according to the present invention can be synthesized using aliphatic dibasic acids as comonomers in the synthesis of PC to react dihydric phenols and carbonate precursors as described above. Such aliphatic dibasic acids may be a substance derived from the structure of Formula 2 below.

Wherein A may be straight, branched or cyclic aliphatic alkylene having no functional group, or may be straight, branched or cyclic aliphatic alkylene containing functional groups such as sulfide, ether, sulfoxide and sulfone. In the present invention, the structure of A is preferably a linear aliphatic alkyl group having 6 to 20 carbon atoms.

The aliphatic dibasic acid is, for example, adipic acid, suberic acid, subzelic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, dodecanedioic acid. Linear saturated aliphatic dibasic acids such as Dodecanedioic acid, Hexadecanedioic acid, Decanedioic acid, and Tetracosanedioic acid; Branched saturated aliphatic dibasic acids; Cyclic saturated aliphatic dibasic acids; And unsaturated aliphatic dibasic acids, but may not be limited to these materials. In order to meet the object of the present invention, sebacic acid and dodecanedioic acid are preferable.

In addition, the amount of mole% may vary depending on the chain length of aliphatic dibasic acid, and the physical properties also vary depending on the content. PEC according to the present invention can be used in the content of aliphatic dibasic acid within 3 to 30 mol% based on the dihydric phenol, preferably 5 to 20 mol%. If the content is less than 3 mol%, the effect on improving the compatibility is insignificant, and if the content is more than 30 mol%, mechanical properties are reduced.

Meanwhile, the above-described PEC that can be used in the present invention may use 5 to 90% by weight, preferably 10 to 70% by weight, based on the total resin composition. If the PEC is less than 5% by weight, the compatibility of the aromatic PC resin with the following COPE is lowered, the mechanical properties such as the impact resistance required is lowered, if more than 90% by weight has a disadvantage of poor chemical resistance.

(C) Copolyester (hereinafter 'COPE'))

Methods of synthesizing COPE are well known and are described in detail in US Pat. No. 2,901,466. COPE is terephthalic acid, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, succinic acid, glutaric acid, adipic acid, sebacic acid and 2,6-naphthalenedicarboxyl One or more dicarboxylic acid compounds such as acids and the like and ethylene glycol, 1,4-cyclohexanedimethanol (hereinafter 'CHDM'), 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1 It can be synthesized using one or more glycol compounds such as, 6-hexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanedimethanol and the like.

The process for preparing copolymer copolymerized polyester using dicarboxylic acid and glycol compound is usually carried out in two stages of ester reaction and polycondensation reaction. The process for preparing COPE using terephthalic acid, CHDM, and ethylene glycol is as follows. Same as

In the first step, the ester reaction is carried out such that total glycol components including ethylene glycol and CHDM are 1.05 to 2.5 in molar ratio with respect to dicarboxylic acid components such as terephthalic acid, and the conditions of 230 to 260 ° C and 0.1 to 0.3 kg / cm ² . Under the following conditions. At this time, the CHDM to be used has an isomer of cis- and trans-, preferably an amount of trans isomer is more than 60%, the reaction temperature is preferably 240 ~ 260 ℃, more preferably 245 ˜255 ° C. In addition, the esterification reaction time usually takes about 100 to 300 minutes, which is affected by the reaction temperature, the pressure and the molar ratio of the monomers used.

In the ester reaction, conventional stabilizers and coloring agents can be used as other additives. Stabilizers can generally be used phosphoric acid, trimethyl phosphate or triethyl phosphate and the like, the content of the stabilizer is 10 to 200ppm relative to the weight of the final polymer based on the amount of phosphorus element. If the addition amount of the stabilizer is less than 10ppm, the effect of stabilization is insignificant, and if it exceeds 200ppm, there is a problem that the desired degree of polymerization cannot be reached. In addition, examples of the colorant added to improve the color include conventional colorants such as cobalt acetate and cobalt propionate, and the addition amount thereof is preferably 10 to 100 ppm relative to the weight of the final polymer. In addition to the colorant, it is also possible to use an organic compound as the colorant.

The second step, the polycondensation step is usually carried out under reduced pressure conditions of 250 ~ 290 ℃ and 400 ~ 0.1mmHg. This polycondensation step is carried out for the required time until the desired intrinsic viscosity is reached, the reaction temperature is preferably 260 ~ 280 ℃. In addition, the polycondensation reaction can be carried out under a reduced pressure of 400 ~ 0.1mmHg in order to remove the glycol produced as a by-product to obtain a COPE copolymerized with CHDM.

Very suitable COPEs for use in the present invention are COPE wherein the glycol moiety has 50 to 70 mole% CHDM and 30 to 50 mole% ethylene glycol and the dicarboxylic acid moiety is terephthalic acid. If the content of CHDM is less than 50 mol% with respect to the total glycol component, there is a problem of opacity when blending with PC. If the amount of CHDM exceeds 70 mol%, it is blended with PC and the impact strength is lowered. A problem arises.

Meanwhile, COPE as described above that can be used in the present invention may use 5 to 90% by weight, preferably 20 to 80% by weight based on the total resin composition. When the COPE is 5 wt% or less, the chemical resistance is lowered, and when the COPE is 90 wt% or more, the impact resistance is inferior.

(D) other additives

On the other hand, the resin composition of the present invention may further include an additive for various purposes, the type and content thereof is according to a person having ordinary knowledge of the present invention. For example, impact modifiers and nucleating agents to improve mechanical properties, lubricants and layer separation inhibitors to improve surface properties, flame retardants to improve chemical properties, UV stabilizers and antioxidants, colorants to improve aesthetic properties (dyes ), Deodorant and deodorant, and a fluidizing agent and a releasing agent for improving the processing properties may be further included.

Typically the blend composition of PC and COPE will be slightly yellowish. The degree of discoloration is affected by the composition, processing temperature and processing conditions. The reason for the yellowing is that the esterification reaction between the PC and COPE is caused by the remaining catalyst during the synthesis of COPE. This yellowing phenomenon can be reduced by adding phosphorus antioxidants during processing. Such phosphorus antioxidants include tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite and bis (4-methyl-2 , 6-di-t-butylphenyl) pentaerythritol diphosphite, or tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene-diphosphonite (Tetrakis (2, 4-di-t-butyl-phenyl) 4,4'-biphenylene-diphosphonite) and the like can be used in combination. Particularly preferred is bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite of formula (3).

It is preferable to use the said phosphorus antioxidant at 0.01-1 weight part with respect to 100 weight part of resin compositions, and it is more preferable to use it at 0.1-0.3 weight part. When the content of the phosphorus antioxidant is less than 0.01 part by weight, the effect of the addition hardly appears, and when it exceeds 1 part by weight, there is a problem such as gas generation during molding.

In the method for producing a resin composition of the present invention, each component is mixed by a conventionally used mixing method, kneaded and extruded by a twin screw melt kneading extruder at a temperature of 240 to 280 ° C. to produce a pellet for molding, and the pellet is It is manufactured by hot air drying at 90-120 ° C. for at least 4 hours. The resin composition thus prepared may be processed through a molding apparatus such as an injection molding machine to manufacture various molded articles.

As such, the resin composition and the molded article using the same according to the present invention have excellent transparency and impact resistance, and have improved chemical resistance to organic solvents.

Hereinafter, the present invention will be described in more detail by explaining preferred embodiments of the present invention and comparative examples for this purpose. However, the present invention is not limited to the following examples, and various forms of embodiments can be implemented within the scope of the appended claims, and the following examples are only common in the art while making the disclosure of the present invention complete. It is intended to facilitate the implementation of the invention to those with knowledge.

The materials used for the test are as follows.

(A) Aromatic PC: PC derived from bisphenol-A, having an intrinsic viscosity of 0.55 dl / g (25 ° C., in methylene chloride).

(B) Copolyester carbonate (PEC): Sebacic acid had a 10 mol% content with respect to bisphenol-A and the intrinsic viscosity was 0.58 dl / g (25 ° C., in methylene chloride).

(C) copolyester (COPE)

(1) COPE I: consisting of 100 mol% terephthalic acid, 30 mol% 1,4-cyclohexanedimethanol and 70 mol% ethylene glycol, intrinsic viscosity 0.77 dl / g (25 ° C., phenol / tetra Chloroethane 50/50 solution).

(2) COPE II: consisting of 100 mol% terephthalic acid, 60 mol% 1,4-cyclohexanedimethanol and 40 mol% ethylene glycol, intrinsic viscosity 0.75 dl / g (25 ° C., phenol / tetrachloro Ethane 50/50 solution).

In addition, the physical properties of the specimens were measured by the following method.

(A) Impact strength: According to ASTM D256, the test piece was notched and evaluated. The final test result is calculated as the average of the test results of five specimens.

(B) Total light transmittance: A specimen of 3 mm thickness was evaluated according to ASTM D1003.

(C) Yellow index (YI): A specimen of 3 mm thickness was evaluated by permeation method in accordance with ASTM D1925.

(D) Instrument Impact Test: Tested in accordance with ASTM D3763, information on how the material behaves under different deformation conditions can be obtained. 3 mm thick, 100 mm diameter disc specimens were measured at 23 ° C. The final test results were calculated as the average of the test results of five test specimens.

Examples 1-6 and Comparative Examples 1-3

Next, the components shown in Tables 1 and 2 were mixed and uniformly dispersed in a Henschel mixer, and then extruded at a temperature of 250 to 280 ° C. in a twin screw melt mixing extruder having L / D = 40 and Φ = 25 mm. The pellets were manufactured in a pellet form, dried in a hot air dryer at 90 ° C. to 120 ° C. for at least 4 hours, and evaluated for physical properties of the specimens injection molded at a temperature of 250 ° C. to 280 ° C. according to the above method. The physical property evaluation results thus measured are shown in Tables 1 and 2 below.

As shown in Table 1 and Table 2, Examples 1 to 6 according to the present invention can be seen to exhibit excellent impact strength while maintaining transparency compared to Comparative Examples 1 to 3. As in Comparative Examples 1 and 2, when the COPE content of 50 mol% or less is blended with PC or PEC, the total light transmittance is opaque to 80% or less, and the impact strength is greatly reduced. As in Comparative Example 3, when blended with COPE and PC having a CHDM content of 60 mol%, the transparency is maintained but the impact strength is lowered.

Example 5 was carried out in the same manner as in Example 6, except that 0.25 parts by weight of bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite was added. Yellow index was measured. As shown in Table 1 below, Example 5, in which the bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite phosphorus antioxidant was added in the case of Example 5, where no antioxidant was used It can be seen that after the injection molding, the yellow index is greatly reduced, thereby improving the color. This is because the phosphorus antioxidant prevents the trans esterification reaction by the residual catalyst of COPE. When a small amount of the phosphorus-based antioxidant is added, the yellow index is reduced and a bright color is obtained, thereby improving transparency and consequently, obtaining a composition having improved transparency and color.

 Example 1  Example 2  Example 3  Example 4  Example 5  Example 6  Composition (% by weight)  PC  45  35  25  15  20  20  PEC  45  35  25  15  20  20  COPE I  -  -  -  -  -  -  COPE II  10  30  50  70  60  60  Antioxidant * (parts by weight)  -  -  -  -  0.25  -  Properties Impact Strength (1/8 ", kg _f cm / cm)  85  74  71  74  70  71  Instrument Impact Strength (J)  82  79  77  81  78  77  Total light transmittance (%)  87  87  87  87  87  87  Yellow Index (YI)  1.9  3.6  4.4  5.3  2.1  4.9

 Bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite

 Comparative Example 1  Comparative Example 2  Comparative Example 3  Composition (% by weight)  PC  50  -  70  PEC  -  50  -  COPE I  50  50  -  COPE II  -  -  30  Antioxidant * (parts by weight)  -  -  -  Properties Impact Strength (1/8 ", kg _f cm / cm)  9  12  13  Instrument Impact Strength (J)  34  36  78  Total light transmittance (%)  65  64  87  Yellow Index (YI)  5.1  5.3  3.8

 Bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite

Comparative Examples 5-6

The composition shown in Table 3 was carried out in the same manner as in Example 1, and a test piece for tensile strength test was obtained through injection molding. In order to evaluate the chemical resistance of the organic solvent, the tensile strength test specimen was mounted on a jig bent at a certain curvature and given 0.8% of strain, soaked in a container containing the organic solvent at 23 ° C. The time at which a crack occurred was measured. The later the crack generation, the better the chemical resistance to the solvent used.

 Example 2  Example 4  Comparative Example 5  Comparative Example 6  Composition (% by weight)  PC  35  15  100  -  PEC  35  15  -  100  COPE II  30  70  -  -  Crack occurrence time (minutes)  Gasoline  15  24  0.5  0.5  Acetone  13  24  One  One  Oleic acid  26  42  10  11

As shown in Table 3, it can be seen that Example 2 and Example 4 significantly increased the time taken for crack generation as compared to Comparative Example 5 and Comparative Example 6 using PC and PEC alone. As a result, the resin composition according to the present invention can be used in molded articles in contact with organic solvents, strong alkalis, fatty acids, oils, and greases in which chemical resistance to organic solvents is greatly improved and the use of conventional PCs is limited.

The polycarbonate / polyester resin composition according to the present invention consists of polycarbonate, polyester carbonate copolymer and copolyester and has excellent impact resistance while maintaining transparency, which is an inherent advantage of polycarbonate. In addition, the chemical resistance to the organic solvent which is a disadvantage of the polycarbonate is greatly improved, it can be usefully used in the applications, such as housings, sheets, films of medical supplies, electrical, electronic materials that require chemical resistance in the future.

Claims (9)

(A) 5 to 90% by weight of an aromatic polycarbonate resin; (B) 5 to 90% by weight of a polyester carbonate copolymer comprising divalent phenols and aliphatic dibasic acids; And (C) 5 to 90% by weight of copolyester resin Thermoplastic resin composition comprising a. The resin composition according to claim 1, wherein the aromatic polycarbonate resin of (A) is at least one selected from the group consisting of linear polycarbonate resins, branched polycarbonate resins, and cyclic polycarbonate resins. The resin composition according to claim 1 or 2, wherein the aromatic polycarbonate resin of (A) has a viscosity average molecular weight (Mv) of 20,000 to 30,000. The resin composition according to claim 1, wherein the aliphatic dibasic acid of (B) is at least one selected from the group consisting of sebacic acid and dodecanedioic acid, and its content is 3 to 30 mol% based on the dihydric phenol compound. . The copolyester of claim 1, wherein the copolyester of (C) comprises a dicarboxylic acid moiety and a glycol moiety, wherein the dicarboxylic acid moiety is terephthalic acid and the glycol moiety is from 50 to 70 mole percent 1,4-cyclohexanedi Methanol and 30-50 mol% ethylene glycol. The resin composition characterized by the above-mentioned. The composition according to claim 1, comprising 10 to 70% by weight of (A) aromatic polycarbonate resin, 10 to 70% by weight of (B) polyester carbonate copolymer, and 20 to 80% by weight of (C) copolyester resin. Resin composition. The resin composition of Claim 1 or 6 which further contains 0.01-1 weight part of phosphorus antioxidant with respect to 100 weight part of resin compositions. The method of claim 7, wherein the phosphorus antioxidant is tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bis (4 -Methyl-2,6-di-t-butylphenyl) pentaerythritol diphosphite, and tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene diphosphonite Resin composition, characterized in that at least one selected from the group. The resin composition according to claim 1 or 6, further comprising an additive selected from the group consisting of colorants, impact modifiers, mold release agents, nucleating agents, ultraviolet light stabilizers and lubricants.