IE41695B1 - Extrusion composition based on glass fibre reinforced vinyl resin - Google Patents

Abstract

1498450 Glass fibre-reinforced vinyl resins PRODUITS CHIMIQUES UGINE KUHLMANN 2 Sept 1975 [13 Sept 1974] 36126/75 Heading C3P An extrusion composition comprises 100 parts by wt. of a vinyl resin of viscosity index 50- 180, 10-60 parts of a mineral filler of 0À05 to 50 micron particle size, 1-5 parts of at least one lubricant and 5-40 parts of glass fibres. In the examples the vinyl resin used is polyvinyl chloride, the mineral fillers are calcium carbonate, calcium magnesium-aluminosilicate and the lubricants are liquid paraffin, glycerol monostearate, oxidized polyethylene wax, 1,2- hydroxystearic acid. Calcium stearate, barium/cadmium laurate, dibasic lead phosphite, dibasic lead stearate, an organic phosphite, and tin butyl mercaptide are also used.

Description

This invention relates to a composition based on vinyl resin, mineral filler glass fibres, and lubricant, which is adaped to be extruded directly in powder form.

The principle of reinforcing thermoplastic and thermo5 setting resins by means of glass fibres is well known.

The incorporation of glass fibres makes it possible to inprove considerably certain mechanical properties, such as the modulus of elasticity or the heat distortion temperature.

In practice the reinforced polymers are processed by 10 discontinuous operation with the aid of compression or injection presses, or by impregnation; the products obtained usually have a satisfactory appearance, with a smooth surface, imperceptible glass fibres, and the reduction or suppression of shrinkage.

Moreover, continuous processes exist which make it possible for glass fibre reinforced tubes to be produced in two stages, as follows; in a first stage a tube is extruded from a thermoplastic material under suitable conditions well known to those skilled in the art; in a second stage, after the outer surface of the tube has been treated for keying purposes external winding is effected with the aid of continuous glass filaments, using a binding to provide the necessary cohesion between the glass and the thermoplastic material.

This technique is used, for example, to produce polyesterwound polyvinyl chloride tubes.

Apart from the fact that this technique comprises two stages, thus entailing additional handling, it also employs heavy and complicated winding equipment. Also, the final mechanical properties of the tube are considerably affected by the properties of the binder.

Numerous attempts have been made to produce continuously extruded sections of glass fibre reinforced thermoplastic materials. In all cases, whatever the nature of the thermoplastic material used/the sections have a rought surface which is readily perceptible by touch and to the eye, so that they are commercially unacceptable.

Furthermore, in their interior the sections are very porous, which means that the products obtained have a certain fragility under impact.

An extrudable composition has been produced which makes it possible for homogenous reinforced objects which have a satisfactory appearance and excellent rigidity to be produced in a single operation. This composition is obtained by judicious association of the following four basic constituents vinyl resin,glass fibres, mineral filler, and lubricant.

According to the present invention there is provided an extrudable composition comprising 100 parts by weight of vinyl resin (as hereinbefore defined) of a viscosity Index from 50 to 180, 10 to 60 parts by weight of mineral filler, the diameter of the particles of the filler being in the range 0.05 to 50 microns, 1 to 5 parts by weight of at least one lubricant, and 5 to 40 parts by weight of glass fibres.

In this Specification the term vinyl resin is used to mean chlorinated polymers, such as polyvinyl chloride, polyvinylidene chloride and superchlorinated polyvinyl chloride, and also the copolymers obtained from the monomer of such a chlorinated polymer and at least one copolymerisable monomer. The viscosity index of the vinyl resin, determined by the standard ISO R 174, must be from 50 to 180 and more preferably from 70 to 120.

Mineral fillers suitable for the composition Of the invention are preferably calcium carbonates, whether or not precipitated and whether or not surface treated, colloidal silicas, hydrated aluminas, calcined clays, and aluminosilicates. The diameter of the elementary particles of the mineral fillers must be from 0.05 to 50 microns, preferably from 0.2 to 10 microns.

Generally speaking, in any given charge of mineral filler, all the particles of filler are not of the same size. Thus, for example a charge of mineral filler having a mean particle size of 0.5 u, usually has a distribution of particles of sizes in the range 0.05 to 50 u, the distribution being such that the average size of the particles is 0.5 u.

Lubricants are selected from'known lubricants. Examples of suitable lubricants are fatty alcohols and acids, esters derived from a fatty acid and an alcohols paraffin waxes, low molecular weight polyethylenes, which may or may not be oxidised. Their melting points are preferably from 50 to 140°C. The glass fibres are those recommended by manufacturers for - 5 their specificity for the vinyl polymer process, and are more particularly cut fibres of short length, preferably of a length from 4 to 6 mm.

As indicated above, in the compositions of the present invention, each 100 parts by weight of vinyl resin is associate# with the following amounts of constituents: (a) from 10 to 60 parts by weight, preferably from 15 to 30 parts by weight, of mineral filler - this considerable amount of filler of very fine particle size when intimately mixed with the resin improves the cohesion of the mixture of resin and glass fibres, with the additional and by no means negligible advantage of lowering the cost price of the composition, (b) from 5 to 40 parts by weight, preferably from 15 to 30 parts by weight, of glass fibres - the association of glass fibres with the composition increases the modulus of elasticity of the basic vinyl resin from 50 to 100% and (c) from 1 to 5 parts by weight, preferably from 1.5 to 3 parts by weight of one or more lubricants. There may be only one lubricant or preferably two or three lubricants, some having a lower melting point and being compatible with the vinyl resin and the others having a high melting point and having relatively poor compatibility with the vinyl resin.

Such a relatively high proportion of lubricant is unacceptable in the prior art for the extrusion processing of a vinyl resin either alone or reinforced with glass fibres, because it prevents any friction between the grains of resin and thus makes it impossible for complete homogeneous fusion to be achieved. It has now surprisingly been found that this relatively high proportion of lubricant is indispensable in the case of the composition forming the object of the present invention. Such an amount of lubricant makes it possible for an amount of - 6 filler which is unusual for a composition containing no plasticiser to be intimately incorporated with the resin.

Any conventional additives suitable for the extrusion process may be associated with the constituents of the composition of the invention. These additives may for example be dyes, modifying agents, stabilisers, and so on. The nature of the stabiliser incorporated in the composition in order to protect the resin against thermal degradation is not important. These stabilisers, which are used in adequate amounts for each type of extruder, may for example be lead, barium or calcium soaps, derivatives of tin, or else phosphorus. products. It is also possible to incorporate plasticisers in these compositions, although this is not necessary.

The various components may be homogenised with one another by the usual techniques for the preparation of extrusion mixtures. The order of introduction of each of the components is of no importance. Nevertheless, it is preferred to mix the different constituents beforehand, with the exception of the glass fibres. The different constituents are stirred at a temperature below 130°C in a high-speed mixer. After the mixture has preferably been cooled to a temperature below 50°C in a slow mixer, for example a ribbon type mixer, the glass fibres are then incorporated in the resulting powder.

This composition.of the invention makes it possible to produce by extrusion, and in a single operation, reinforced objects, such as sections, tubes, and the like, which have improved properties, for example being free from internal porosities and having excellent rigidity and a smooth surface with adequate amounts of mineral filler.

The invention will now be further described with reference to the following Examples. In the Examples and Comparative Examples the quantities are expressed in.parts by weight.

Examples 1 to 4 and Comparative Examples 1 and 11.

The compositions which were prepared and the results obtained are summarised in the table below. With the exception of the glass fibres, the various components are mixed together in a high-speed mixer for a sufficient time to obtain a homogeneous mixture, while allowing the temperature to rise to 120°C.

The glass fibres are then incorporated in the mixture, which is cooled to 40°C, in a slow ribbon type mixerExamples 1 to 4.

The resultant composition is extruded at from 160 to 190°C in a single-screw extruder with a diameter of 60mm and a length of 1,200 mm, the extruder having tool equipment permitting the production of a tube of an outside diameter of 32 mm and a thickness of 2.6 mm. The cooling fixture following the die has a length of 300 mm and the sizing of the tube is effected by vacuum.

Example 5. 2o By the procedure given in Examples 1 to 4, a composition of the following formula is prepared and extruded. {polyvinyl chloride, viscosity index 75 100 dibasic lead phosphite 3 dibasic lead stearate 1 glass fibres, length 6 mm 20 calcium carbonate (mean diameter: 0.5 micron) 20 1-2-hydroxystearic acid 0.5 oxidised polyethylene wax AC 629A-melting point 105°C 0.5 calcium stearate 0.5 A tube is obtained which is free from porosity and has a smooth surface, a Young's modulus of flexural regidity of 55,000 kg/cm , and a heat distortion temperature of 81°C.

Example 6 By the procedure of Examples 1 to 4 a composition of the following formula is prepared and extruded: polyvinyl chloride, viscosity index 105 100 10 tin butylmercaptide modifying agent PLASTIFLO A01 glass fibre, length 6 mm calcium-magnesium aluminosilicate (mean diameter: 0.2 micron) 1.5 1 20 20 15 liquid paraffin glycerol monostearate oxidised polyethylene wax AC 629A -melting point 105°C 0.6 1.2 0.3 A tube is obtained which has a smooth outer surface and a 20 Young's modulus of flexural rigidity of 60,000 kg/cnr. in vo Γ- o CM O o o o’ o H o CM CM rd m m in in Q CM d O O O o o cn O CM CM rd in n in in o CM d o o o o' o CM O CM r-i rd in m in • o • • o CM O CM I O O rd o H m m n rM o CM o 1 o o o’ rd O rd rd in co m o 03 d 1 | o d r—1 o rd φ X •rl Λ Ui Ui 0 33 (¾ ·· tf — o 0 Φ Pl X o rd tf 0) 13 tf g 0 >! tn tf -rd Φ tf •tf £ T3 0 ΤΪ tf in Φ · cn X Η O CM ίΧ tf a —· VO X tf •r| g X y co tf 0 Φ tf u Ti ft Jj to tf g tf tf g pi T3 s > Φ IH VO tf •ri X Φ a Φ a tf XQ e tf tf Φ tf 4J f) α) υ Ti tf tn υ HO •td tf tf X •tf >tn tf Φ 0 +1 tf 33 O Φ o tf tf X H X es m tf Φ Φ tf tn X tf -co 0 X >i+> tf w □ to co X to H tf tf fjj ε Φ tf >1 0 -tf Φ *§ «_> tf to tf N E3j 0 X S Sx tf 33 ω 0 O ft to 9 PS u Q •rd tf tf Ti C5 S X H g Ti Φ tn e 3 > g d cn 3 1» W Pl tf 3 to tf •rd X •rd Ή •H ίχ •tf Sx (0 Φ U Ό +1 O tf XI ifl 33 rd CM •rd rd H 0 tf o rd *tf tf ίί 2 tf .....ftL. CQ ft O ft u r—1 ο s u ο U3 tf X 0) X CH 0 0 s £ o ω X I _o X tf O Γ in o t-in o vo in o o CM o vo fM Ti ω tf •rl ztf CM χ ε X o tn AJ ίΧ X •tf •rl X (Ω ιϋ H Φ x o to tf rtf tf Τί tn o 0 -rl Cn X X X tn tf φ tf X (0 X υ CU I X o X tf Ti N H ω S3 o Φ vo § *27 tn Cn O g 8 0 Q tf XJ I tf —0— ft X 0 W O Q) OO Cn tf tf υ Ο ·η n e -tto vo tf Γ* 0 c 0) tn O to £ g 0 0 to X Φ tf Φ Cn o w £ g 0 0 X Φ Φ tf tf X □ tf tf X to τί tf tf Φ tf tf tf tf Φ ft nJ Φ tf X tf tf M υ T5 tf o tf φ Ti tf tf φ tf tf x tf tf φ ft tf o •tf X tf X (0 •rl Q

Claims (10)

CLAIMS:

1. An extrudable composition comprising 100 parts by weight of vinyl resin (as hereinbefore defined) of a viscosity index from 50 to 180, 10 to 60 parts by 5 weight of mineral filler, the diameter of the particles of the filler being in the range 0.05 to 50 microns, 1-to 5 parts by weight of at least one lubricant, and 5 to 40 parts by weight of glass fibres.

2. A composition according to Claim 1, wherein the 10 particles of the filler have a diameter in the range 0.2 to 10 microns.

3. A composition according to either of Claims 1 or 2, comprising from 15 to 30 parts by weight of mineral filler

4. A composition according to any one of Claims 1 to 3, 15 wherein the lubricant has a melting point of from 50°C to 140°C.

5. A composition according to any one of claims 1 to 4, whereih the lubricant is a mixture containing at least one low melting point lubricant which is compatible with 20 the vinyl resin.

6. A composition according to any one of the preceding claims, wherein 1.5 to 3 parts by weight of at least one lubricant is used.

7. A composition according to any one of the preceding 2 g Claims, wherein from 15 to 30 parts by weight of glass fibres of a length of from 4 to 6 mm are used.

8. A composition according to any one of the preceding claims prepared by incorporating the glass fibres into a mixture comprising the vinyl resin, the mineral filler, 20 and the lubricant.

9. An extrusion composition substantially as hereinbefore described with reference to any one of Examples 1 to 4.

10. An extruded article obtained using a composition 5 according to any one of Claims 1 to 9.