GB1568625A

GB1568625A - Polybutylene terephthalate-polycarbonate moulding compositions

Info

Publication number: GB1568625A
Application number: GB8173/77A
Authority: GB
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1976-03-01
Filing date: 1977-02-25
Publication date: 1980-06-04
Also published as: MX143880A; JPS52121659A; FR2343023A1; DE2708381A1; BR7701274A; AU2275277A; FR2343023B1; AU512954B2; NL7702101A

Description

(54) POLYBUTENE TO REPHTHALATE-POLYCARB ONATE MOULDING COMPOSITIONS (71) We, GENERAL ELECTRIC COMPANY, a corporation organized and existing under the laws of the State of New York, United States of America, of 1 River Road, Schenectady 12305, State of New York, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a thermoplastic moulding composition which comprises poly(1,4-butylene terephthalate), a polycarbonate resin and a reinforcing amount of a reinforcing filler.

Poly (1,4-butylene terephthalate) resins are well known and have been widely employed for the production of thermoplastic molded articles. Also reinforced compositions of poly (1,4butylene terephthalate) have been commercially available for a number of years.

These compositions are useful for á plurality of applications especially when a high degree of solvent resistance is required. Glass fibre reinforced polyl,4-butylene terephthalate) when molded into various articles has a tendency to become distorted or warped especially when the molded article has a thin section.

It has been found that if a polycarbonate resin is added to the reinforced poly(1,4butylene terephthalate) moulding composition, the molded articles are substantially resistant to warpage or distortion after they are removed from the mold. This result is achieved without any appreciable decrease in the mechanical, physical or molding properties of a typical glass reinforced poly(1,4-butylene terephthalate) molding composition.

Compositions of polyalkylene terephthalate and polycarbonate resins have been described in U.S. 3218372. These unreinforced compositions are described as having a reduced melt viscosity and as having a higher ductility than the polycarbonate and polyalkylene terephthalate resins.

The present invention provides a thermoplastic molding composition which comprises in 100 parts by weight of the compositions: a from 95 to 20 parts by weight of the composition of poly(1,4-butylene terephthalate); from 5 to 80 parts by weight of the composition of a polycarbonate resin of recurring units of the formula:

wherein each - R - is phenylene, or alkyl substituted phenylene, and X and Y are each hydrogen, hydrocarbon radicals free from aliphatic unsaturation of radicals which together with the adjoining

atom form a cycloalkane radical, the total number of carbon atoms in X and Y being up to 12; - {c) a reinforcing amount of a reinforcing agent.

The present invention also provides a method of making a thermoplastic composition for a thermoplastic moulded article which method comprises including 5 to 80 parts by weight of pplycarbonate resin having recurring units of the formula:

wherein each - R - is phenylene, or alkyl substituted phenylene, and X and Y hydrogen, hydrocarbon radicals free from aliphatic unsaturation of radicals which together with the adjoining

atom forms a cycloalkane radical, the total number of carbon atoms in X and Y being up to 12, in 100 parts by weight of a thermoplastic composition that comprises from 95 to 20 parts by weight poly(1,4-butylene terephthalate) resin and a reinforcing agent in an amount sufficient to prevent distortion of the molded article.

The poly(1,4-butylene terephthalate) should preferably have an intrinsic viscosity between 0.4 and 1.2 dl/g. as measured at 300C in a 60/40 solution of phenol/tetrach loroethane. A more preferred range is between 0.6 and 0.9 dl/g.

The preferred polycarbonate resins may be derived from the reaction of bisphenol-A and phosgene. These polycarbonates have from 100-400 recurring units of the formula:

The polycarbonates are described in U.S. patents 3,028,365, 3,334,154 and 3,915,926.

The polycarbonate should preferably have an intrinsic viscosity between 0.3 and 1.0 dl/g, more preferably from 0.3 to 0.45 dl/g as measured at 20"C in methylene chloride.

The reinforcing agents may be selected from for example, finely divded aluminium, iron or nickel and non-metals, such as carbon filaments, silicates, such as acicular calcium silicate, asbestos, titanium dioxide, wollastonite, potassium titanate and titanate whiskers, glass flakes and fibers.

Although it is only necessary to use a reinforcing amount of the reinforcing agent, from 1-60 parts by weight of the total weight of the composition may comprise the reinforcing agent. A preferred range is from 5-40 parts by weight.

The preferred reinforcing agents are of glass, and it is preferred to use fibrous glass filaments. The preferred filaments for plastics reinforcement are made by mechanical pul- ling. The filament diameters can range from 0.u112 to 0.00075 inch, but this is not cirtical to the present invention.

The preferred compositions will include from 90 to 65 parts by weight of poly(1,4 butylene terephthalate) and from 10 to 35 parts by weight of a polycarbonate resin.

The composition may be prepared by any standard procedure and the particular method employed is not critical.

The composition may also include flame retardants such as those disclosed in U. S.

3,915,926.

EXAMPLE 1 The following composition was prepared by blending the materials in an extruder: Parts by weight poly(1,4-butylene terephthalate* 62.8 polycarbonate resin** 7.0 glass fibers 1/8" (Owens Corning P219A) 30.0 stabilizers*** 0.3 This composition had the following physical properties: * 4000 MW poise melt viscosity ** Lexan124 *** Irganox 1093 and Ferro 904 (50/50) Melt viscosity 19,836 Heat distortion temperature 392"F Izod impact (notched) 1.82 ft. Ibs./in.n.

Elongation % 5.21 Tensile yield 17,728 psi Flexural yield 28,158 psi Flexural modulus 1.029 x 106 psi Specific gravity 1.5330 Flex. Elongation 3.96% EXAMPLE 2 The following composition was prepared by blending the materials in an extruder: Parts by weight poly(1,4-butylene terephthalate) * 55.8 polycarbonate resin ** 14.0 glass fibers 1/8" (Owens Corning P219A) 30.0 stabilizers*** 0.2 This composition had the following physical properties: * 4000 poise meltviscosity ** Lexan*124 *** Irganox* 1093 0.15 and Ferro * 904 0.5 * Registered Trade Mark Melt viscosity 21,204 Heat distortion temperature 374"F Izod impact (notched 1.83 ft.lbs./in.n.

Elongation % 5.14 Tensile yield 18,125 psi Flexural yield 28,713 psi Flexural modulus 1.074 x 106 psi Specific gravity 1.5311 Flex. Elongation 3.83% EXAMPLE 3 The following composition was prepared by blending the materials in an extruder: Parts by weight poly(1,4-butylene terephthalate) * 48.8 polycarbonate resin ** 21.0 glass fibers 1/8" (Owens Corning P219A) 30.0 stabilizers*** 0.2 This composition had the following physical properties: * 4000 poise meltviscosity ** Lexan* 124 *** Irganox*1093 0.15 and Ferro * 904 0.05 * Registered Trade Mark Melt viscosity 20,064 Heat distortion temperature 335 F Izod impact (notched) 1.79 ft.lbs./in.n.

Elongation % 5.14 Tensile yield 18,125 psi Flexural yield 27,841 psi Flexural modulus .982 x 106 psi Specific gravity 1.4724 Flex. Elongation 4.23 % EXAMPLE 4 The following composition was prepared by blending the materials in an extruder: Parts by weight poly(1,4-butylene terephthalate)* 41.8 polycarbonate resin ** 28.0 glass fibers 1/8" (Owens Corning P219A) 30.0 stabilizers * * * 0.3 This composition had the following physical properties: * 4000 MW poise melt intensity ** Lexan * 124 *** Irganox * 1093 and Ferro 904 * (50/50) * Registered Trade Mark Melt viscosity 24,624 Heat distortion temperature 292"F Izod impact (notched) 2.11 ft.lbs./in.n.

Elongation % 5.14 Tensile yield 18,240 psi Flexural yield 28,951 psi Flexural modulus 1.081 x 106 psi Specific gravity 1.4870 Flex. Elongation 3.69% EXAMPLE 5-13 The following compositions were prepared by melt blending the components in an extruder: (All parts are by weight) 5 6 7 8 9 10 11 12 131 poly(1,4butylene terephthalate)* 41.85 35.85 29.85 49.85 42.85 35.85 47.85 39.85 100 polycarbonate resin** 28 24 20 20 17 14 12 10 glass fibers 1/8" (Owens Corning P219A) 30 40 50 30 40 50 40 50 stabilizers*** 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 mold release 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 * Valox* 095 295 ** Lexan* 121 *** Ferro* 904 1 Control * Registered Trade Mark.

The composition of Example 5 to 13 were tested and found to have the following physical properties: 5 6 7 8 9 10 11 12 13 Specific Gravity 1.491 1.573 1.652 1.507 1.609 1.719 1.589 1.645 Tensile Break 18,900 19,800 19,500 18,200 19,700 20,500 19,800 21,700 Izod Impact (notched) ft.lbs./in.n. 2.1 2.5 2.2 2.0 2.2 2.2 2.1 2.6 Heat Distortion 320 350 318 360 376 381 392 395 (264 psi) F 315 340 331 350 380 384 391 Warp AM 0 0 0 0.2 1.3 3-6 6.5 4.0 24-31 1/2 hr. 350 F 17 17 21 19 20 21 22 21 30

Claims

WHAT WE CLAIM IS:

1. A thermoplastic molding composition which comprises in 100 parts by weight of the compositions: (a) from 95 to 20 parts by weight of the composition of poly(1,4-butylene terephthalate); (b) from 5 to 80 parts by weight of the composition of a polycarbonate resin of recurring units of the formula:

wherein each - R - is phenylene, or alkyl substituted phenylene, and X and Y are each hydrogen, hydrocarbon radicals free from aliphatic unsaturation or radicals which together with adjoining

atom form a cycloalkane radical, the total number of carbon atoms in X and Y being up to 12; and (c) a reinforcing amount of a reinforcing agent.

2. A thermoplastic molding composition as claimed in Claim 1 wherein the polycarbonate has the repeating unit

3. A thermoplastic molding composition as claimed in claim 1 or claim 2 wherein the polycarbonate resin consists of from 100 to 400 repeating units.

4. A thermoplastic molding composition as claimed in any one of Claims 1 to 3 which rises: (a) from 95 to 20 parts by weight of poly(1 4 -butylene terephthalate); (b) from 5 to 80 parts by weight of polycarbonate resin; (c) from 1 to 60 parts by weight of filamentous glass.

5. A thermoplastic molding composition as claimed in any one of Claims 1 to 4 which includes a flame-retardant amount of a flame-retardant agent.

6. A method of making a thermoplastic composition for a thermoplastic molded article which method comprises including 5 to 80 parts by weight of polycarbonate resin having recurring units of the formula:

wherein each - R - is phenylene, or alkyl substitued phenylene, and X and Y are hydrogen, hydrocarbon radicals free from aliphatic unsaturation or radicals which together with the adjoining

atom forms a cycloalkane radical, the total number of carbon atoms in X and Y being up to 12, in 100 parts by weight of a thermoplastic composition that comprises from 95 to 20 parts by weight poly(1,4 -butylene terephthalate) resin and a reinforcing agent in an amount sufficient to prevent distortion of the molded article.

7. A method as claimed in Claim 6 wherein the polycarbonate has the repeating unit

8. A method as claimed in Claim 6 or Claim 7 wherein the polycarbonate consists of from 100 to 400 repeating units.

9. A method as claimed in any one of claims 6 to 8 wherein the reinforcing agent is filamentous glass.

10. A method as claimed in any one of claims 6 to 9 wherein the composition further includes a flame retardant agent.

11. A thermoplastic molding composition as claimed in Claim 1 substantially as hereinbefore described in any one of the Examples 1 to 12.

12. A method of making a thermoplastic composition for a molded article as claimed in Claim 6 substantially as hereinbefore described in any one of Examples 1 to 12.

13. A composition when produced by a method as claimed in any one of Claims 6 to 10 and 12.