GB2236531A

GB2236531A - Halogen containing resin

Info

Publication number: GB2236531A
Application number: GB9021688A
Authority: GB
Inventors: Hiroshi Takida; Teruo Iwanami; Yoshimi Akamatsu; Kazuya Hori
Original assignee: Mitsubishi Kasei Vinyl Co; Nippon Synthetic Chemical Industry Co Ltd
Current assignee: Mitsubishi Kasei Vinyl Co; Nippon Synthetic Chemical Industry Co Ltd
Priority date: 1989-10-07
Filing date: 1990-10-05
Publication date: 1991-04-10
Anticipated expiration: 2010-10-05
Also published as: JP2903089B2; FR2652814A1; FR2652814B1; JPH03124752A; DE4031294C2; GB9021688D0; GB2236531B; DE4031294A1

Abstract

Halogen-containing thermoplastic resin compositions comprise a halogen-containing thermoplastic resin (A) consisting of 100 to 0.1 weight percent of a thermoplastic polyurethane-vinyl chloride polymer alloy (al) with a polyurethane content of 10 to 90 weight percent and 0 to 99.9 weight percent of another halogen-containing polymer (a2) and a melt-moldable vinyl alcohol polymer (B), the proportion of melt-moldable vinyl alcohol polymer (B) being in the range of 0.1 to 100 parts by weight to 100 parts by weight of halogen-containing thermoplastic resin (A).

Description

4 HALOGEN-CONTAINING THERMOPLASTIC RESIN COMPOSITION

BACKGROUND OF THE INVENTION

This invention relates to a halogen-containing thermoplastic resin composition excelling in processability, appearance, strength, hydrophilicity, resistance to oils and solvents and gas barrier property.

Vinyl chloride polymers are not only comparatively inexpensive but also have high clarity and excellent mechanical properties and have therefore been used in a variety of applications, such as film, sheet, hose, flexible containers, coated fabric, artificial leather, tarpaulin, shoe bottom, sponge, electrical wire sheathing, household utensils and so on.

Having the above-mentioned advantages on the one hand, vinyl chloride polymers are disadvantages, on the other hand, in that they are not satisfactory in processability, hydrophilicity, resistance to oils and solvents, gas barrier property and adhesiveness to substrates.

In order to improve the processability, hydrophilicity and other properties of vinyl chloride polymers, it has been practiced to polymerblend these resins with a modifying resin such as a hydrolyzed ethylene-vinyl acetate copolymer.

2 By way of example,-Japanese Patent Application KOKAI No. 69955/1977 discloses a polyvinyl chloride barrier packaging composition essentially comprising a mixture of a vinyl chloride polymer and an ethylene- vinyl alcohol copolymer, the proportion of which is 10 to 30 weight percent based on the vinyl chloride polymer.

Japanese Patent Application KOKAI No. 238345/1985 describes a resin composition comprising (a) a thermo- plastic resin (including polyvinyl chloride), (b) a hydrolyzed ethylene- vinyl acetate copolymer, and (c) a salt or an oxide containing at least one element selected from the group consisting of the elements of Groups I, II and III of Periodic Table of the Elements and mentions that this composition has remarkably improved compatibility.

Japanese Patent Publication No. 59-39464 discloses a vinyl chloride polymer-polyurethane alloy obtainable by reacting a polyol with a polyisocyanate in the presence of a vinyl chloride polymer. However, this literature does not refer to a combination of such polymer alloy with a vinyl alcohol polymer.

The incorporation of a hydrolyzed ethylene-vinyl acetate compolymer in a halogen-containing thermo- plastic resin such as a vinyl chloride polymer results 3 - in improvements in hydrophilicity, resistance to oils and solvents and gas barrier property, the inherent poor compatibility of the two resins makes long-run molding difficult and, moreover, the products obtainable therefrom by melt molding have foreign matter and discoloration problems as well as poor mechanical properties.

The composition according to Japanese Patent Application KOKAI No. 238345/1985 referred to above offers improved compatibility but the degree of improvement by addition of a salt or oxide has its own limit and it still has much room for improvement.' The object of this invention is to solve the above-mentioned problems by using.a certain alloyed polymer mixture as at least part of the halogen-con- taining thermoplastic resin in adding a vinyl alcohol polymer to a halogen-containing thermoplastic resin for improving its properties.

SUMYARY OF THE INVENTION This invention is therefore directed to a halogen containing thermoplastic resin composition comprising parts by weight of a halogen-containing thermo plastic resin composed of 100 to 0.1 percent by weight of a vinyl chloride polymer-polyurethane alloy (al) with a polyurethane content of 10 to 90 percent by 4 weight which is obtainable by reacting a polyol with a polyisocyanate in the presence of-.a vinyl chloride polymer and 0 to 99.9 percent by weight of a different halogen-containing polymer (a2) and 0.1 to 100 parts by 5 weight of a melt-moldable vinyl alcohol polymer (B).

DETAILED DESCRIPTION OF THE INVENTION

This invention is described in further detail hereinafter.

Halogen-containing thermoplastic resin (A) The halogen-containing thermoplastic resin (A) is either a vinyl chloride polymer-polyurethane alloy (al) or a mixture of said alloy (al) and a different halo gen-containing polymer (a2).

Alloy (al) is The vinyl chloride polymei-polyurethane alloy (al) is produced by reacting a polyol with a polyisocyanate in the presence of a vinyl - chloride polymer..

This reaction can be carried out advantageously as follows.

The polyol is added to the vinyl chloride polymer in powdery or granular form for impregnation, followed by addition of the polyisocyanate so that a poly urethane is formed in the powdery or granular particles of said vinyl chloride polymer. Another reaction method comprises mixing the powdery or granular vinyl chloride polymer, polyol and polyisocyanate together to produce a polyurethane.

The polyurethane content of the resulting alloy should be within the range of 10 to 90 percent by weight. When the polyurethane content is less than the above range, the effect of improving the compatibility of the polymers is sacrificed.

The term 'vinyl chloride polymer' as used in this specification and the claims appended thereto means not only a vinyl chloride homopolymer but any copolymer of vinyl chloride with one or more other comonomers such as vinyl acetate, ethylene, vinylidene chloride and so on.

of the materials for urethanation, the poylol includes polyester polyols (condensed polyester polyols, lactone-type polyester polyols, polycarbonate diols, etc.) and polyether polyols. Among the condensed polyester polyols are reaction products of dicarboxylic acids such as adipic acid, succinic acid, azelaic acid, pimellic acid, sebacic acid, phthalic acid, etc.) or lower alkyl esters thereof with linear aliphatic diols (such as ethylene glycol, 1,4-butane diol, 1,6-hexanediol, 1,10-decamethylene glycol, etc.) or aliphatic diols having side chains (such as 1,2 propylene glycol, 1,3-butanediol, 2,5-dimethyl-2,5- 6 hexanediol, 2,2-diethyl-1,3-propanediol, neopenty! glycol, etc.). Among the polyether polyols are polyethylene glycol, polypropylene glycol, polytetramethylene glycol, glycerin-based polyalkylene glycol and so on.

of the materials for urethanation, the polyisocyanate includes aliphatic or alicyclic diisocyanates such as tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, cyclohexylmethane diisocyante, 2,2,4- or 2,4,4trimethylhexamethylene diisocyanate, isopropylidenebis(4-cyclohexyl isocyanate), methylcyclohexane diisocyanate, isophorone diisocyanate, etc. 2,4-or 2,6-tolylene diisocyanate, diphenylmethane is 4,41-diisocyanate, 3-methyldiphenylmethane-4,41-di- isocyanate, m- or p-phenylene diisocyanate, chlorophenylene-2,4- diisocyanate,' naphthalene-1,5-diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate and polyalcohol-polyisocyanate adducts, among others.

In conducting the urethanation reaction, a chain extender such as a polyhydric alcohol, a polyamine or the like can be employed.

A different halogen-containing polymer (a2) As examples of the halogen-containing polymer (a2) 7 other than said alloy (al), there may be mentioned vinyl chloride polymer, vinylidene chloride polymer, chlorinated polyethylene, chlorinated polypropylene, ethylene chloride-vinyl acetate copolymer, chloro- sulfonated polyethylene and so on. Particularly desirable are vinyl chloride polymers, i.e. homopolymer of vinyl chloride and copolymers of vinyl chloride with other comonomers. Vinyl alcohol polymer (B) The vinyl alcohol polymer (B) includes, among others, melt-moldable vinyl alcohol homopolymers and copolymers, such as polyvinyl alcohols of comparatively low degrees of polymerization, partially hydrolyzed polyvinyl acetates, post-modification (acetalized, ketalized and cyanoetherized) products of polyv--nyl alcohols, and hydrolyzed copolymers of vinyl acetate with various monomers copolymerizable therewith (e.g. olefins such as ethylene, propylene, isobutene, aoctene, 6-octadecene, etc., unsaturated carboxylic acids or salts, partial alkyl esters, alkyl esters, nitriles, amides or anhydrides thereof, unsaturated sulfonic acids or salts thereof, vinyl esters other than vinyl acetate, etc.). It should be understood, however, that the proportion of the monomer or monomers copolymerizable with vinyl acetate should not be more 8 than 30 mole percent, except that, in the case of ethylene, its proportion should not exceed 75 mole percent.

Among the above-mentioned polymers, a hydrolyzed ethylene-vinyl acetate copolymer with a degree of saponification of vinyl acetate (ethylene content 20 75 mole %, preferably 25 - 60 mole %) being not less than 50 mole percent (preferably not less than 70 mole percent) is the most useful. The vinyl alcohol poly- mers outside the above copolymer composition are inadequate in the potential to improve the properties of halogen-containing thermoplastic resin (A) It should also be understood that as long as the above mentioned range of copolymer composition is met with, is the vinyl alcohol polymer (B) may contain other comonomers in minor proportions.

Among those vinyl alcohol polymers (B), a low-ash, low-alkali metal vinyl alcohol polymer with a melting point not exceeding 2000C and ash and alkali metal contents not exceeding certain limits is particularly useful.

Since the halogen-containing thermoplastic resin (A) is generally molded at a temperature not higher than 2000C, any vinyl alcohol polymer (B) with a melting point exceeding 2001C will not be completely 9 dispersed in (A) and, hence, the physical properties of the resulting product may not be fully satisfactory.

Moreover, if the ash content are/or alkali metal content of (B) exceeds a certain limit, the halogen- containing thermoplastic resin is liable to undergo discoloration and decomposition.

The hydrolyzed vinyl acetate copolymer can generally be prepar ed by hydrolyzing (saponifying) a vinyl acetate copolymer with the aid of an alkali catalyst.

However, the industrial water and reagents used generally contain metal salts as impurities and the saponification catalyst (an alkali metal hydroxide) remains as the alkali metal acetate after the reaction, with the result that such impurities and alkali metal acetate tend to be contained in the saponified polymer separated by precipitation or filtration from the saponification reaction mixture. Though it depends on various factors such as the comonomer content of the resin, degree of saponification, conditions of saponification reaction, etc., the ash and alkali metal contents of the hydrolyzed vinyl acetate copolymer so obtained are usually about 5,000 to 50,000 ppm and about 4, 000 to 40,000 ppm, respectively.

In the production of polyvinyl alcohol or a modification product thereof, an acid or an alkali is used as the catalyst. W7hen an acid is used as the catalyst, a metal hydroxide or a carbonate is used in the neutralization stage after the reaction. Therefore, a fair amount of alkali metal is inevitably 5 contained.

The terms lash content' are used herein to mean the value found as follows. The hydrolyzed vinyl acetate copolymer is dried, taken in a platinum evaporating dish and carbonized by means of an electric heater and a gas burner. The carbonized resin is then charged into an electric furnace maintained at 4000C. The furnace temperature is then increased to 7000C, at which temperature it is thoroughly reduced to ashes in 3 hours. The ashes are taken out from the furnace, allowed to cool for 5 minutes and further allowed to stand in a desiccator for 25 minutes. Finally, the ashes were accurately weighed.

The terms 'alkali metal content' are used herein to mean the value found as follows. After the hydro- lyzed vinyl acetate copolymer is reduced to ashes as in the determination of ash content, the ashes are dis solved in an aqueous solution of hydrogen chloride under warming and the solution is subjected to atomic absorption spectrometry.

The hydrolyzed ethylene-vinyl acetate copolymer to be used in accordance with the invention preferably has an ash content, as determined by the above procedure, of not more than 300 ppm. more desirably not more than 50 ppm, and for still better results not more than 20 ppm and an alkali metal content, also as determined by the above- described procedure, not more than 200 ppm, more desirably not more than 35 ppm, and for still better results not more than 5 ppm. The ash and alkali metal contents are preferably as low as possible within the respective ranges mentioned above but because of various limitations imposed on purification in commercial production, the practical lower limits are about Ippm for ashes and about 0.5 ppm for alkali metal.

The aforementioned ash- and alkali metal-lean vinyl alcohol copolymer can be prepared as follows. The powders, granules or pellets of said vinyl alcohol copolymer are washed thoroughly with an acid, preferably a solution of a weak acid in water or an organic solvent such as methanol, to remove the salt responsi- ble for said ashes and alkali metal and are then preferably washed with water or an organic solvent such as methanol to remove the absorbed acid from the resin and dried.

Incidentally, the water to be used in the prepara- 12 tion of aqueous solutions or in the washing procedure is deionized water and the same applies to the following description.

As examples of the weak acid mentioned above, there may be mentioned acetic acid, propionic acid, glycolic acid, lactic acid, adipic acid, azelaic acid, glutaric acid, succinic acid, benzoic acid, isophthalic acid, terephthalic acid and so on. Generally, a weak acid with a pKa value not less than 3.5 at 250C is preferred.

After the above weak acid treatment and either before or after washing with water or an organic solvent such as methanol, there is preferably carried out a further treatment with a dilute aqueous solution of strong acid, for example an organic acid with a pKa value not exceeding 2.5 at 250C, such as oxalic acid, maleic acid, etc., or a mineral acid such as phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid and so on. By this strong acid treatment, removal of the alkali metal can be more effectively accomplished. Formulation The proportion of said vinyl chloride polymerpolyurethane alloy (al) in said halogen-containing thermoplastic resin (A) must be within the ragne of 0.1 to 100 weight percent, with the balance being accounted 13 - for by the halogen-containing polymer (a2) such as ordinary vinyl chloride polymer. If the proportion of the alloy (al) is less than 0.1%, the compatibility with the vinyl alcohol polymer (B) will be inadequate, with the result that the appearance and physical properties of moldings will be adversely affected.

The proportion of the vinyl alcohol polymer (B) to each 100 parts by weight of the halogen-containing thermoplastic resin consisting of said alloy (al) and other halogen-containing polymer (a2) is selected within the range of 0.1 to 100 parts by weight. The preferred range is 0.5 to 50 parts by weight.

If the proportion of vinyl alcohol polymer (B) is too small, the improving effect on the properties of halogen-containing thermoplastic resin (A) will not be sufficient, while the use of vinyl alcohol polymer (B) in excess of the above-mentioned range will detract from the inherent useful properties of halogen- containing thermoplastic resin (A).

Other additives The halogen-containing thermoplastic resin composition of this invention may include, in addition to the above-described components, various additives which are conventionally used for polyvinyl chloride resin, such as plasticizers, antioxidants, stabilizers, 14 auxiliary stabilizers, ultraviolet absorbers, dyes and pigments, fillers, lubricants, antistatic agents, surfactants, chelating agents, reinforcing materials, foaming agents, flame retardants, impact resistance improving agents and so on. Furthermore, unless the object and effect of this invention are not jeopardized, other kinds of thermoplastic resins can also be incorporated.. Compounding sequence The vinyl chloride polymer-thermoplastic poly- urethane alloy (al) and other halogen-containing polymer (a2), vinyl alcohol polymer (B) and any other additives can be compounded simultaneously or in an optional order and the resulting compound is subjected. is to melt-molding.

Melt-molding As the melt-molding techniques that can be employ ed, any of calender molding, extrusion molding, injec tion molding and blow molding methods can be employed.

EFFECTS.OF THE INVENTION In accordance with the invention wherein, in the melt-molding of a polymer blend consisting of a halo gen-containing thermoplastic resin (A) and a vinyl alcohol polymer (B), a certain vinyl chloride polymer- polyurethane alloy (al) is used as at least part of said halogen-containing'thermoplastic resin (A), the lack of compatibility between the vinyl alcohol polymer (B) and halogen- containing thermoplstic resin (A) is effectively improved, with the result that the mold- ability of the composition and the ameliorating effect of vinyl alcohol polymer (B) on the physical properties of halogen-containing thermoplastic resin (A) are remarkably improved.

Therefore, in calender molding, the problem of elplateout" is eliminated, while extrusion molding can be continuously carried out over a long run. Moreover, the discoloration of moldings is effectively inhibited and the appearance and physical properties of moldings are remarkably improved.

EXAMPLES

The following examples are further illustrative of this invention.

- Provision of materials - As the halogen-containing thermoplastic resin (A) and vinyl alcohol polymer (B), the following materials were provided.

Halogen-containing thermoplastic resin (A) - Alloy (al) (al-1) One part by weight of calcium stearate was mixed 16 with 1 part by weight of zinc stearate and the mixture was milled in a Henshel mixer at a high speed for 2 minutes to prepare a polyvinyl chloride powder with a degree of polymerization of 1,100. To 100 parts of this polyvinyl chloride was added 100 parts by weight of a polyester polyol with a molecular weight of 2,000 as prepared by condensing adipic acid with 1,4-butanediol/neopentyl glycol (mol ratio 9/1) and previously heated at 700C. The mixture was stirred at 1000C for 10 minutes, after which 9 parts by weight of tolylene diisocyanate was added. The temperature was increaased to 1100C and the reaction mixture was further stirred at this temperature for 1 hour to carry through the urethanation reaction.

The reaction mxiture was cooled to room tempera- ture to give a polyvinyl chloride-polyurethane alloy. The polyurethane content of this alloy was 52%i (al-2) Using 100 parts by weight of a particulate poly- vinyl chloride with a degree of polymerization of 1,100, 1 part by weight of calcium stearate, 1 part by weight of zinc stearate, 40 parts by weight of a polyester polyol prepared by condensation of adipic acid with 1,4-butanediollneopentyl glycol (mol. ratio 17 - 9/1) and 5 parts by weight of diphenylmethane diisocyanate, a particulate polyvinyl chloride-polyurethane alloy was produced under otherwise the same conditions as for (al-1). The polyurethane content of this alloy 5 was 30%. (al-3) Using 100 parts by weight of a particulate polyvinyl chloride with a degree of polymerization of 1,100, 1 part by weight of calcium stearate, 1 part by weight of zinc stearate, 140 parts by weight of a polyester polyol with a molecular weight of 2,000 as prepared by condensation of sebacic acid with 1,6hexanediol, and 12 parts by weight of tolylene diisocyanate, a polyvinyl chloride-polyurethane alloy was produced under otherwise the same conditions as for (al-1). The polyurethane content of this alloy was 60%.

- Other halogen-containing polymer (a2) (a2-1) Polyvinyl chloride (degree of polymerization: ROO) (a2-2) Vinylidene chloride-methyl acrylate copolymer (methyl acrylate: 7 mole %) Vinyl alcohol polymer (B) (B-1) 18 Hydrolyzed ethylene-vinyl acetate copolymer (ethylene content 44 mole degree of saponification of vinyl acetate 99.5 mole m.p. 1670C, ash content 6 ppm, sodium metal content 2.7 ppm) (B-2) Hydrolyzed ethylene-vinyl acetate copolymer (ethylene content 55 mole degree of saponification of vinyl acetate 79.0 mole m.p. 1110C, ash content ppm, sodium metal content 4.0 ppm) (B-3) Dodecene-1-vinyl acetate copolymer hydrolyzate (dodecene-1 content 5.5 mole %, degree of saponifica tion of vinyl acetate 99.3 mole %, m.p. 1870C, ash content 215 ppm, sodium metal content 140 ppm) (B-4) Polyvinyl alcohol (degree of polymerization 500, degree of saponification 70.0 mole %, m.p. 1700C, ash content 120 ppm, sodium metal content 70 pprO - Formulation and molding conditions - Using the above materials in the proportions indicated in Table 1, preliminary compounding was carried out and, then, the respective compounds were extrusion-molded under the conditions described herein after. Hereinafter, all parts are by weight.

However, in the case where halogen-containing 19 - thermoplastic resin (a2) was polyvinyl chloride, the compounding formula and molding conditions were as follows.

(Compounding formula) Alloy (al) As indicated Polyvinyl chloride (a2) As indicated (100 parts for (al) and (a2) combined) Vinyl alcohol polymer (B) As indicated Epoxidized soybean oil 3 Parts Calcium stearate 0.5 Part Zinc stearate 0.5 Part Stearoylbenzoylmethane 0.2 Part (Extrusion molding conditions) Extruder: a 30 mm (dia.) extruding machine T die: 200 mm wide, sheet thickness 0.3 mm Screw: Fullflight constant pitch, L/D=20, compression ratio 3.0, rotational speed rpm.

Temperature: Cl: 1300C, C2: 175'C, C3: ISO'C H: 1700C, D: 180'C Screen: 80 mesh x 2 Takeup roll: 85 - 901C When the halogen-containing thermoplastic resin (a2) is a vinylidene chloride-methyl acrylate copolymer, the compounding formula and extrusion molding condi- tions were set as follows.

(Compounding formula) Alloy (al) As indicated Vinylidene chloride s methyl acrylate copolymer (a2) As indicated (100 parts for (al) and (a2) combined) Vinyl alcohol polymer (B) As indicated Epoxidized soybean oil 3 Parts Calcium stearate 0.5 Part Zinc stearate 0.5 Part Stearoylbenzoylmethane 0.2 Part (Molding conditions) Extruder: a 40 mm (dia.) extruding machine Screw: LID-23, compression ratio 3.2; 30 rpm (Other conditions are the same as for the extrusion process described hereinbefore).

The conditions and results are shown in Table 1.

T Table 1

Compounding formula Molding trouble Appearance of Properties of product product Total light Impact Discharge Component/parts transmittance strength2 half-time (%) - Wg3CM/CM (sec.) al-1 100 Coloration: None Example 1 B-1 10 No trouble PE: None 87 Not destroyed 55 Streaks: None al-1 30 Coloration: None Example 2 a2-1 70 No trouble PE: None 83 > 74 28 B-1 20 Streaks: None al-1 20 Coloration: None Example 3 a2-1 80 No trouble PE: None 79 > 56 30 B-2 20 Streaks: None al-1 30 Coloration: None Example 4 a2-1 70 No trouble PE: None 85 > 61 25 B-3 10 Streaks: None al-2 100 Coloration: None Example 5 B-2 10 No trouble PE None 86 Not destroyed so Streaks None al-2 70 Coloration: None Example 6 a2-1 30 No trouble PE None 84 Not destroyed 25 B-4 5 Streaks None al-2 80 Coloration: None Example 7 a2-2 20 No trouble PE: None 85 Not destroyed 28 B-4 5 Streaks: None al-3 100 Coloration: None Example 8 B-3 5 No trouble PE: None 87 Not destroyed 30 Streaks: None al-3 100 Coloration: None Example 9 B4 5 No trouble PE: None 87 Not destroyed 29 Streaks: None al-3 25 Coloration: None Example 10 a2-1 75 No trouble PE: None 83 > 70 55 B-1 20 Streaks: None Table 1 (Continued) Compounding formula Molding trouble Appearance of Properties of product product Total light Impact Discharge Component/parts transmittance strength2 half-time (%) (kg3cm/cm (sec.) Comparative a2-1 100 Flash, flow Coloration: yellow Example 1 B-1 10 mark, surging PE: multiple 70 3 180 Streaks: S Comparative a2-1 100 Flash, flow Coloration: yellow Example 2 B-2 10 mark, surging PE: multiple 75 3 250 Streaks: S Comparative a2-1 100 Flash, flow Coloration: yellow Example 3 B-3 5 mark, surging PE: multiple 55 2 200 Streaks: S a2-2 100 Flash, flow Coloration: yellow Comparative B-4 5 mark, surging PE: multiple 60 2 250 K) Example 4 Streaks: S (Note) In the "appearance of producC column, "Streaks: S" means that there are streaks.

The determination and evaluation were made as follows.

The extrusion-moldability was evaluated in terms of draw-down, change in torque and other abnormalities during 8-hours continuous molding.

The appearance of molded testpieces were evaluated after 8-hours continuous molding in terms of discolora tion, fisheyes (FE), streaks and so on.

The total light transmittance was measured in accordance with JIS K 6745 (1 mm-thick sheet).

As to impact strength, Izod impact strength was measured in accordance with JIS K 7110. In the table, Onot destroyed" means that 10 specimens were invariably not destroyed and >74, >70, >61 and >S6 means that the minimum values for 10 specimens were 74, 70, 61 and 56, respectively.

The discharge half-time was measured with an honestmeter. With the halogen-containing thermoplastic resin (A) alone, the discharge half-time was - for any of (al-1), (al-2), (al-3), (a2-1) and (a2-2) or any mixture thereof.

24

Claims

What is claimed is: 1. A halogen-containing thermoplastic resin

composition comprising 100 parts by weight of a halogencontaining thermoplastic resin (A) composed of 100 to

0.1 percent by weight of a vinyl chloride polymer-polyurethane alloy (al) with a polyurethane content of 10 to 90 percent by weight which is obtainable by reacting a polyol with a polyisocyanate in the presence of a vinyl chloride polymer and 0 to 99.9 percent by weight of a different halogen-containing polymer (a2) and 0.1 to 100 parts by weight of a melt-moldable vinyl alcohol polymer (B).
2. A composition according to Claim 1 wherein said vinyl alcohol polymer (B) is a low-ash, low-alkali metal vinyl alcohol polymer with a melting point not exceeding 2000C, an ash content not exceeding 300 ppm, and an alkali metal content not exceeding 200 ppm.
3. A composition according to Claim 1 wherein said vinyl alcohol polymer (B) is a hydrolyzed ethylene- vinyl acetate copolymer with an ethylene content of 20 to 75 mole percent and a degree of saponification of vinyl acetate not less than 50 mole percent.
4. A composition according to Claim 3 wherein said hydrolyzed ethylene-vinyl acetate copolymer is a low-ash, low-alkali metal ethylene-vinyl acetate copolymer with a melting point not exceeding 200 0 cl and ash content not exceeding 300 ppm and an alkali metal content not exceeding 200 ppm.
5. A halogen containing thermoplastic resin substantially as described herein by reference to any one of the Examples.

Published 1991 at The Patent Office. State House, 66171 High Holborn. London WC1 R 47P. Further copies nlay be obtained frorn Sales Branch. Unit
6. Nine Mile point. Cwmfeltrifach. Cross Keys. Newport. NPI 7HZ. Printed by MultipIrx techniques lid. St Mary Cray. Kent.

1 - --- -------------.. -- ---- -j -1- - mdry kray. nent.