NL8001890A - MODIFIED POLYESTER MATERIALS. - Google Patents

Description

S 2348-1019 f

P&C

Modified polyester materials.

The invention relates to modified thermoplastic, polyester-containing materials that are moldable into articles with improved impact strength and physical strength. More particularly, the invention relates to materials containing (a) a block copolyester of poly (1,4-butylene terephthalate) or a combination thereof with a polyester modified with (b) an effective amount of a polyacrylate resin. The invention also provides materials which further comprise (c) filler and / or reinforcement material and / or (d) a flame retardant.

Linear polyesters and copolyesters of glycols and terephthalic acid or high molecular weight isophthalic acid have been available for a number of years. These materials are described, inter alia, in U.S. Patents 2,465,319 and 3,047,539. These U.S. patents disclose that the polyesters are particularly advantageous as film and fiber-forming materials.

With the development of molecular weight control and the use of nucleating agents and two-step molding operations, poly (ethylene terephthalate) has become an important constituent of injection moldable compositions. Because of its very fast crystallization from the melt, poly (1,4-butylene terephthalate) is particularly suitable as a component in these compositions. Workpieces formed from these polyester resins and optionally reinforcing agents have a high degree of hardness and wear resistance, a strong gloss and a low surface friction, compared to other thermoplastic materials.

Stable mixtures of poly (1,4-butylene terephthalate) and poly (ethylene-25 terephthalate) can be formed into useful, unarmed and armed articles, see U.S. Patent 3,953,394.

Block copolyesters containing units of poly (1,4-butylene terephthalate) and of an aromatic / aliphatic or aliphatic polyester are known, see German Offenlegungsschrift 2,756,167. These block copolyesters 30 are suitable as molding resins in themselves and also in intimate combination with poly (1,4-butylene terephthalate) and / or poly (ethylene terephthalate).

. It has been proposed to increase the impact strength of polyesters by adding various modifiers. For example, U.S. Patent 3,591,659 describes a suitable group of modifying agents, namely polyalkyl acrylates, methacrylates and / or ethacrylates.

U.S. Patent 4,044,073 discloses that for polyesters, an aromatic polycarbonate is a suitable impact modifier. U.S. Pat. No. 4,022,748 discloses that a rubber 8001890-2 elastic graft copolymer having a glass transition temperature below -20 ° C is a suitable modifier. U.S. Pat. Nos. 4,034,013 and 4,096,202 disclose that multi-phase polymers having a rubbery first phase and a hard last 5 phase, preferably containing units derived from alkyl acrylates, especially butyl acrylate, suitable as impact modifiers. US patent application 957,801 describes a modifying combination for the impact resistance, namely a mixture of a polyalkyl acrylate and an aromatic polycarbonate.

Although filler containing and / or reinforced and / or flame retardant modifications of the above materials are described in the above references, these materials lack one or more desirable properties in the molded state. In addition, all of these materials are generally somewhat difficult to extrude into a predetermined shape. It has now been found that block copolyesters of poly (1,4-butylene terephthalate) and combinations thereof with poly (1,4-butylene terephthalate) and / or poly (ethylene terephthalate) are greatly improved in terms of extrudability and impact resistance, both untreated and after a heat treatment and at about -29 ° C, by intimately mixing as a modifier only a polyacrylate resin, for example without added aromatic polycarbonate resin. As can be seen from the following, the present new materials can contain a filler and / or be reinforced, for example with glass, and / or made flame-retardant.

The invention provides thermoplastic materials suitable for molding operations, for example injection molding, compression molding, press injection molding and the like, and in particular suitable for extrusion operations, which materials contain: (a) a polyester material, namely: (i a block copolyester of poly (1,4-butylene terephthalate) and an aromatic / aliphatic or aliphatic polyester; (ii) a mixture of (i) and a poly (ethylene terephthalate) resin; or (iii) a mixture of (i) and a poly (1,4-butylene terephthalate) resin; and (b) an agent for modifying the polyester material, namely a polyacrylate resin in an amount of up to 60 parts by weight per 100 parts by weight of (a) + (b).

The block copolyester used in (a) can be prepared by transesterification of (a) straight or branched chain poly (1,4-butylene terephthalate) and (b) a "copolyester" of a linear aliphatic dicarboxylic acid and optionally an aromatic dibasic acid such as terephthalic acid or iso-8001890 t-3-phthalic acid, with one or more straight or branched divalent aliphatic glycols. For example, one can mix a poly (1,4-butylene terephthalate) with a "copolyester" of adipic acid and ethylene glycol and heat at 235 ° C to melt the ingredients; it is then heated further under reduced pressure until the formation of the copolyester is complete. As a second component, it is also possible to use poly (neopentyl adipienate), poly (1,6-hexylene-azelaienate-coisophthalate), poly (1,6-hexylene-adipienate-coisophthalate) and the like. These methods and products are described in U.S. patent application 752,325. A suitable copolyester as defined under (a) (i) is marketed by the General Electric Company under the name "VALOX 330".

The polyester resins used as components of (a) (ii) and (a) (iii) are commercially available or can be prepared by known methods, for example, by alcoholysis of esters of terephthalic acid and ethylene glycol, by heating glycols with the free acids or with halide derivatives thereof, and similar methods. These methods are described, inter alia, in U.S. Patents 2,465,319 and 3,047,539.

For example, the high molecular weight polyesters can have an intrinsic viscosity of at least about 0.4 dl / g at 3Q®C in a mixture of phenol and tetrachloroethane (60:40); preferably this intrinsic viscosity is at least 0.6 dl / g.

When high melt strength is important, particularly suitable are poly (1,4-butylene terephthalate) resins with a high melt viscosity, containing a small amount, for example up to 5 mol%, based on the terephthalate units, of a branching component with at least three ester-forming groups. The branching component may provide branching in the acid unit portion or in the glycol unit portion of the polyester or it may be a hydride. Examples of these branching components are tri and tetracarboxylic acids, such as trimesinic acid, pyrimellitic acid and lower alkyl esters thereof, and the like, and - preferably - polyols, especially tetrols, such as pentaerythritol, and triols, such as trimethylolpropane, and dihydroxycarboxylic acids and hydroxydicarboxylic acids and derivatives thereof.

The branched poly (1,4-butylene terephthalate) resins and the preparation of these materials are described in U.S. Patent 3,953,404.

The impact modifier (b) is a polyacrylate resin. These materials can be prepared by known methods 8001890-4 - and are commercially available from various manufacturers, for example, the products marketed by Rohm & Haas Company under the names "Acryloid", "KM330" and "7709XP". Other suitable polyacrylates include the following products: Goodyear Tire & Rubber Co. product marketed under the designation "RXL6886"; the product marketed by the American Cyanamid Company under the name "Cyanacryl 770"; it by Μ & T Chemicals Co. product marketed under the name "Durostrength 200"; and the product marketed by Polysar Corporation (Canada) under the name "Polysal S1006". Generally, any of the polyalkyl acrylates described in U.S. Patent 3,591,659 may be used, especially those containing units derived from n-butyl acrylate. Preferably, the polyacrylate resin is a rubber-elastic graft copolymer having a glass transition temperature below 20 ° C, as described in U.S. Patent No. 4,022,748. The polyacrylate is particularly preferably a multi-phase polymer with a rubbery first phase and a thermoplastic hard final phase, as described in U.S. Patent 4,096,202.

According to certain preferred embodiments, the materials contain fibers, in particular reinforcing fibers, such as glass fibers, or mineral fibers, such as clay, mica, talc and the like, preferably clay. The fillers may be untreated or treated with silane or titanate (coupling agents) etc. The glass fibers to be used as reinforcement in these embodiments of the invention are known materials which are widely available and are marketed by a number of manufacturers brought. For materials that are ultimately used for electrical applications, it is preferable to use fibrous glass filaments composed of calcium aluminum borosilicate glass which is relatively free of sodium. This material is known as "E" glass. However, other glasses are also suitable when the electrical properties are not so important, for example the low sodium glass known as "G" glass. The wires are manufactured according to standard methods, for example by steam or air blowing, flame blowing and mechanical stretching. Preferably, the wires used to reinforce plastics are made by mechanical stretching. The diameters of the wires range from about 3 to about 19 microns, but this is not critical to the invention.

Also the length of the glass threads is not critical, nor is it critical whether or not the threads are bundled into fibers and these fibers 800 1 8 90 - 5 - in turn into yarns, cords or slivers, or mats and the like are woven. In the preparation of the molding materials, however, it is convenient to use the filamentary glass in the form of chopped strands about 3.2 mm to about 5.1 cm in length. In contrast, even shorter pieces occur in articles formed from the present materials, since significant breakage occurs during assembly. However, this is desirable since the best properties are exhibited by thermoplastic injection molded articles in which the length of the wires is between about 13 microns and about 6.4 mm.

The amount of filler can vary within wide limits, depending on the composition and the requirements for the material in question. Preferably, however, the amount of filler is about 1-60% by weight of the combination of filler (c) and components (a) and (b). Especially preferably, the amount of filler is less than about 40% by weight of the combination.

It has further been found that even relatively small amounts of modifier (b) are effective in providing a significant improvement in impact strength and the like. Generally, the modifying agent (b) is present in an amount of at least about 1 wt% and preferably in an amount of about 2.5 - 50 wt% based on (a) and (b) .

The modified polyesters, whether or not combined with glass and / or filler, can be rendered flame retardant with an effective amount of a conventional flame retardant (d). Known flame retardants are elemental red phosphorus, phosphorus compounds, halogen compounds and nitrogen compounds, optionally in combination with synergists such as antimony compounds. Particularly suitable are polymers and oligomeric flame retardants containing tetrabromobisphenol A carbonate units, see, for example, U.S. Patent No. 3,833,685.

It is also possible to add other ingredients, such as dyes, pigments, anti-drip dripping agents, and the like for their usual purposes.

The materials of the invention can be prepared by a number of methods. According to one of these methods, the modifying agent and optionally used filler and / or reinforcing glass and / or flame retardant with the resin (s) used as component (s) are introduced into an extruder mixer to obtain molding granules. The modifier and the other ingredients are dispersed in a matrix of the resin.

8001890 * - 6 -

In another method, the modifying agent and any reinforcing glass and / or flame retardant used, if desired, are mixed with the resins by a dry mixing method, after which the mixture is smoothed on a roller and crushed or extruded and chopped. The modifier (optionally combined with other ingredients) can also be mixed with the resins and formed directly, for example, by injection molding or compression molding.

It is always important to free as much as possible of all components, namely resin, modifying agent, reinforcing agent and / or filler and / or flame retardant and any usual additives used.

Furthermore, the composition should be carried out such that the residence time in the machine is short, the temperature is carefully controlled, the frictional heat is utilized, and an intimate mixture of resin and modifier and optionally other ingredients are obtained.

Although this is not essential, the best results are obtained if the ingredients are premixed, granulated and then shaped or extruded. The pre-mixing can be performed in conventional equipment. For example, after careful pre-drying of the polyester and the modifier (eg, for 12 hours at 100 ° C under reduced pressure), a dry mixture of the ingredients can be introduced into a single screw extruder, which screw has a long transition portion property to ensure proper melting. Alternatively, a twin screw extruder, for example, a 53 mm Werner-Pfleiderer machine, may be used, adding resin and additives at the feed port and the reinforcement downstream thereof. In both cases, a generally suitable temperature in the machine is approximately 232® - 293®C.

The pre-formulated mixture can be extruded by conventional methods and comminuted to form materials such as conventional granules, tablets, etc.

The composition can be molded in any device commonly used for thermoplastic materials, for example, a Newbury type injection molding machine, with conventional cylinder temperatures, for example, about 232® - 280®C, and conventional molding temperatures, for example, about 54® - 93®C.

preferred embodiments

The invention is further illustrated in the following non-limiting examples.

8001890 * - 7 -

EXAMPLES I-IV

A dry blend of a block copolyester of poly (1,4-butylene terephthalate) and an aromatic / aliphatic polyester, optionally poly * (ethylene terephthalate), and further polybutyl acrylate resin and a mold release agent / stabilizer was formulated and at about 271® C extruded in an extruder. The extrudate was granulated and injection molded at about 266 C (mold temperature 66 C). The compositions and physical properties are given in Table A.

TABLE A

Materials containing a block copolyester, optionally a polyester, and polyacrylate resin

Example 1 II III IV

Composition (parts by weight)

Poly (1,4-butylene terephthalate- 89.9 79.8 69.8 67.3 copolyester)

Poly (ethylene terephthalate) - - - 10.0

Polyacrylate rubber ^ 10.0 20.0 30.0 22.5

Mold release agent / stabilizer (up to 100 parts by weight) 20 Properties

Distortion temp. (®C) at approx.

1820 kPa 42.8 42.2 41.7 45

Notch impact value glv. Izod,

Joule / cm (0.32 cm) 0.96 5.82 9.02 8.43 25 Impact strength acc. Izod None None None None (without notch), Joule / cm fracture fracture fracture fracture

Flexural strength, kPa 51,000 42,100 37,200 46,900

Flexural modulus, kPa 1,247,900 1,013,500 999,700 1,185,900

Tensile strength, kPa 30,300 26,900 22,800 29,600 30% Elongation 277 246 232 180 (a) (i) Valox 330, General Electric Co., PBT / aromatic-aliphatic polyester.

(b) Acryloid KM330, Rohm & Haas Co., Am.octr. 4,096,202, a multi-phase polymer with a rubbery first phase 35 and a thermoplastic hard final phase.

From the above, it can be seen that the materials of the invention exhibit excellent impact resistance. They are also excellent for extrusion operations.

EXAMPLE V

The general procedure of Example I was used to prepare a composition of a block copolyester of poly (1,4-butylene terephthalate), 8001890-8 - a polyacrylate resin and glass fibers as a reinforcing agent. The composition used and the properties obtained are given in Table B.

TABLE B

Materials containing polyester, polyacrylate and glass as 5 reinforcement__

Example V

. Composition (parts by weight)

Block copolyester of poly (1,4-butylene terephthalate) (a) (i) 67.3 10 Polyacrylate rubber ^ 22.5

Glass fibers 10.0

Stabilizing agent / mold release agent (up to 100 parts by weight)

Properties 15 Distortion temp. (®C) at ca.1820 kPa 106.7

Notched impact value acc. Izod, Joule / cm (0.32 cm) 2.13

Impact resistance acc. Izod (without notch), Joule / cm 8.33

Flexural strength, 65,500 kPa

Flexural modulus, kPa 1,795,300 20 Tensile strength, kPa 45,500% Elongation 16.3 (a) (i) Valox 330, see Table A.

(b) Acryloid KM330, See Table A.

In particular, the composition had excellent impact resistance.

EXAMPLE VI

A flame-retardant, unreinforced material with modified impact strength was prepared according to the general procedure of Example I. The composition and results are given in Table C.

8001890

- 9 TABLE C

Materials containing block copolyester, graft copolymer, polyacrylate and flame retardant __

Example VI

5 Composition (parts by weight)

Block copolyester of poly (1,4-butylene-44.3 terephthalate)

Polyacrylate rubber '22.5

Copolycarbonate of mixture of bisphenol-A 10 and tetrabromobisphenol-A 28.0

Antimony Oxide 5.0

Stabilizing agent / mold release agent (up to 100 parts by weight)

Properties 15 Distortion temp. (®C) at ca.1820 kPa 53.3

Notched impact value acc. Izod, Joule / cm 6.94

Impact resistance acc. Izod, without notch, Joule / cm No breakage

Flexural strength, 54,810 kPa

Flexural modulus, kPa 1,447,900 20 Tensile strength, kPa 32,400% Elongation 75

Flammability, UL Bull 94 V-0 (a) (i) Valox 330, General Electric Co.

(b) Acryloid KM330, see Table A.

8001890

Claims (12)

A thermoplastic material, characterized by: (a) a polyester material, namely: (i) a block copolyester of poly (1,4-butylene terephthalate) and an aromatic / aliphatic or aliphatic polyester; (ii) a mixture of (i) and a poly (ethylene terephthalate) resin; or (iii) a mixture of (i) and a poly (1,4-butylene terephthalate) resin; and (b) a modifier for the polyester material, namely a polyacrylate resin in an amount of up to 60 parts by weight per 100 parts by weight of 10 (a) + (b). The material according to claim 1, characterized in that modifier (b) is present in an amount of at least about 1.0 part by weight per 100 parts by weight (a) + (b). Material according to claim 2, characterized in that modifier 15 (b) is present in an amount of about 2.5 - 50 parts by weight per 100% by weight. parts (a) + (b). Material according to claims 1-3, characterized in that each polyester in component (a) has an intrinsic viscosity of at least about 0.4 dl / g, determined at 30 ° C in a solution in a mixture of phenol and tetrachloroethane (60:40), possession. Material according to claim 4, characterized in that each polyester in component (a) has an intrinsic viscosity of at least about 0.6 dl / g, determined at 30 ° C in a solution in a mixture of phenol and tetrachloroethane (60: 40). Material according to claims 1 to 5, characterized in that the poly (1,4-butylene terephthalate) resin of component (a) (iii) is linear or branched. 7. Material according to claim 6, characterized in that the branched polyester is a poly (1,4-butylene terephthalate) resin with a high melt viscosity, which resin contains a small amount of a branching component with at least three ester-forming groups. Material according to claims 1-7, characterized in that the polyacrylate resin (component (b)) contains units derived from n-butyl acrylate. 9. Material according to claims 1-8, characterized in that the poly-35 acrylate is a multi-phase polymer with a rubbery first phase and a thermoplastic hard last phase. Material according to claims 1-9, characterized in that the material also (c) a filler and / or a reinforcing agent in an amount of about 1-60 parts by weight per 100 parts by weight (a) + (b) + (c) contains. 8001890 - 11 - Material according to claim 10, characterized in that component (c) is formed by glass fibers. 12. Material according to claims 1-11, characterized in that the material also contains (d) a flame-retardant amount of a flame-retardant. 8001890