NO174260B - Grafted sequence polymers, their preparation and use as well as polymer alloys obtained by the copolymers - Google Patents

Abstract

The invention is in the field of plastics and relates to grafted block copolymers. Another subject of the invention is the synthesis of these grafted block copolymers. They are obtained by grafting and radical polymerisation of a monomeric composition on backbone-polymers whose units exhibit a block distribution. The invention also relates to the use of these grafted block copolymers are blend emulsifying agents and their use for the manufacture of moulded or extruded articles, films, sheets, etc.

Description

The present invention relates to new grafted sequence copolymers: polymers called graft are grafted onto skeleton polymers, hereafter more simply called skeleton.

More specifically, the invention relates to grafted sequence copolymers whose stem, based on polyether polyester amides, consists of block polyester or block polyamide parts, distributed sequentially.

The invention also relates to a method for producing these grafted sequence copolymers, the use of the copolymers and polymer alloys obtained with the aid of the sequence copolymers.

JP publ. 63-41 558 describes the synthesis of a flexible thermoplastic resin produced by polymerization in an aqueous medium of a monomer mixture based on vinyl chloride in the presence of a monomer-soluble thermoplastic polyurethane.

US-PS 3,549,700 relates to non-grafted block copolymers. JP application 033,497 describes polyetheramide block copolymers with hydrophilic grafts such as acrylic acid. These products serve to improve textile properties with regard to water absorption and antistatic properties. Finally, FR-PS 2,418,807 describes polyether polyester block copolymers which are copolymerized with unsaturated compounds with carboxylic acid functions and OH groups. According to a variant, the polyether polyester block copolymers are grafted with unsaturated products with amide or epoxy functions. The obtained polymers are intended for vulcanization.

The present invention aims to improve the known technique and therefore relates to grafted sequence copolymers of the type mentioned at the outset and these copolymers are characterized by

i) that at least one sequence of the stem is soluble in monomer-

the mixture from which the graft originates and that at least one sequence

of the stem is insoluble in the monomer mixture, and

ii) that the grafts are made with vinyl chloride, vinylidene chloride, chlorotrifluoroethylene, methyl, ethyl, butyl or 2-ethylhexyl (meth)acrylate, styrene, α-methylstyrene or vinyl acetate.

Among the preferred mixtures should be mentioned those which, in addition to vinyl chloride, contain an alkyl (meth)acrylate (and possibly vinylidene chloride), or vinyl acetate or chlorotrifluoroethylene, as well as mixtures based on styrene and alkyl (meth)acrylate.

Block copolymers based on polyester or a polyamide should be mentioned as examples of block copolymers which can form skeletons of grafted block copolymers according to the invention. In general, these block copolymers belong to the class of thermoplastic elastomers, TPE; they exhibit a sequential distribution of the constituent units of rigid blocks and of flexible blocks.

Among these block copolymers, special mention should be made of: polyester-based block copolymers in which the rigid phase consists of polyester sequences produced, for example, from polybutylene or polyethylene terephthalate, these sequences being copolymerized with flexible sequences consisting, for example, of a glycol with a low molecular weight in

combination with a polyalkylene ether glycol;

block copolymers based on polyamide in terms of rigid sequences and polyether flexible sequences, which are also called polyether amides.

These block polyether amides can in particular arise from copolycondensation of polyamide sequences containing reactive ends with polyether sequences containing reactive ends such as:

a) polyamide sequences containing diamine chain ends with polyoxyalkylene sequences containing dicarboxyl chain ends; b) polyamide sequences containing dicarboxylic chain ends with polyoxyalkylene sequences containing diamine chain ends, obtained by cyanoethylation and hydrogenation of aliphatic a,a)-dihydroxylated polyoxyalkylene sequences,

called polyetherdiols;

c) polyamide sequences containing dicarboxylic chain ends with polyether diols, the polyether amides obtained, in

in this case polyetheresteramides, are commercially available, among others, from the present applicant.

Such products are, for example, described in FR-PS 74/18 913 and 77/26 678.

The number average molecular weight for these polyamide sequences is generally between 500 and 10,000 and more particularly between 600 and 5,000. The polyamide sequences of the polyether ester amides preferably consist of polyamide 6, 66, 612, 11 or 12, or of copolyamides which arise from polycondensation of their monomers.

The number average molecular weight for the polyethers is generally between 200 and 6,000 and more particularly between 600 and 3,000.

The polyether sequences preferably consist of polytetramethylene glycol, PTMG, polypropylene glycol, PPG or polyethylene glycol,

PEG.

The intrinsic viscosity of the polyetheresteramides is preferably between 0.8 and 2.05.

The limiting viscosity is measured in metacresol at 20° C with an initial concentration of 0.5 g per 100 g metacresol. The polyether ester amides according to the invention can consist of 5 to 85 wt-# of polyether and 95 to 15 wt-# of polyamide, preferably 30 to 80 wt-# of polyether and 70 to 20 wt-# of polyamide.

As mentioned at the outset, the invention also relates to a method for producing the described grafted sequence copolymers and this method is characterized by radical grafting of the monomer mixture and radical polymerization of the stem.

The monomer mixture not only initiates grafting onto the backbone via a radical mechanism, but also polymerizes via a radical mechanism to form grafted polymers.

According to the present description, a radical polymerization is intended to mean a polymerization in the presence of a polymerization initiator which forms free radicals.

The polymerization methods that are usually used are suitable for the synthesis of grafted sequence copolymers according to the invention.

Mass polymerization and suspension polymerization can be mentioned.

In general, the polymerization/grafting temperature is between 30 and 100°C, preferably between 35 and 80°C.

The polymerization initiators are usually organosoluble compounds. They can be chosen from organo-soluble polymerization initiators that are usually used in suspension polymerization, examples are organic peroxides such as lauryl, benzoyl, acetylcyclohexanesulfonyl, isobutyryl, dichloroacetyl and trichloroacetyl peroxide, peroxydicarbonates such as ethyl, ethylhexyl, isopropyl, isobutyl - and dicetylperoxydicarbonate, tert-butylmethoxyperacetate, tert-butylethoxyperacetate and tert-butyl-2-phenoxyperpropionate. 0.001 to 0.10 weight #, calculated on the monomers used, of the initiator or initiators is generally used, this expression calculated as active oxygen.

In the suspension polymerization process, the reaction mixture used comprises water, the skeleton polymers and a monomer mixture as indicated above, possibly a stabilizer and at least one organo-soluble polymerization initiator as indicated above.

The stabilizing agent can be chosen from those usually used in suspension polymerization, examples are polyvinyl alcohol, methyl celluloses, carboxy celluloses and gelatins.

The amount of stabilizer used is generally between 0.04 and 1 wt-# of the monomer mixture and the skeleton polymers that are supplied.

The amount of water used is chosen so that the initial content of monomer mixture and skeleton polymers is generally between 30 and 80% by weight of the total reaction mixture.

The skeleton polymers are introduced into the reaction mixture in powder form with an average particle size that is generally between 20 and 200 µm, or in granule form with an average particle size that is generally between 200 µm and 5 mm, preferably between 500 µm and 4 mm.

When the skeleton polymers are introduced in granular form into the reaction mixture, the presence of a stabilizing agent during the polymerization is an eventual feature.

On the other hand, formulation aids can be added after the polymerisation, examples of which are heat stabilizers, lubricants, antioxidants, pigments and so on.

The monomer mixture can be introduced into the reaction mixtures at the beginning of the reaction, but also continuously during the entire duration of the suspension polymerization.

When the polymerization/grafting is complete, the grafted block copolymers can be isolated from the reaction mixture by any known method such as filtration, decanting or centrifugation, and can be dried and optionally sieved or ground.

In mass polymerization, the reaction mixture comprises the backbone polymers, a monomer mixture and at least one radical polymerization initiator.

It is all carried out in a reactor where the stirring must be sufficient to ensure good homogeneity during the polymerisation/grafting reaction on the granulate of skeleton polymers.

The degree of grafting of the monomer mixture onto the backbone polymer can be measured by selective extraction. For example, to measure the degree of grafting of a monomer mixture on skeleton polymers based on polyether ester amides, a selective extraction of the products obtained by the polymerization/grafting reaction as described above is primarily carried out in isopropanol or hexafluoroisopropanol.

Only the polyetheresteramide (which forms the backbone polymers) is soluble in alcohols; the grafted block copolymers as well as the polymers derived solely from the monomer mixtures introduced are insoluble. The amount of backbone polymers based on polyetheresteramide that are not grafted by the monomer mixture can thus be determined.

In a second step and to determine the amount of polymers derived exclusively from the monomer mixture, i.e. those not grafted onto the backbone polymers, the product obtained is dissolved in tetrahydrofuran, THF, after which isopropanol or hexafluoroisopropanol is added to selectively precipitate polymers derived exclusively from the monomer mixture.

A further object of the invention is the use of these sequence copolymers for the production of molded or extruded objects.

In cases where the monomer mixture contains vinyl chloride, the copolymers obtained must be formulated. For example, you can use additives or additives that are usually used when formulating PVC or copolymers thereof, examples are heat stabilizers, lubricants, fillers and so on.

Tin and barium/cadmium salts can be mentioned as examples of heat stabilizers. Polyethylene waxes can be mentioned as examples of lubricants.

In those cases where the skeleton polymers are introduced in granular form, the formulation additives are added after polymerization/grafting and before degassing of the monomer mixture in this takes place to enable the excipients to migrate directly into the granule cores.

The graft copolymers according to the invention can be converted into molded articles by conventional injection or compression molding or formed into tubes, films, extruded cable coverings and molded articles using calendering, extrusion or blowing/extrusion.

As mentioned at the outset, the invention also relates to the use of the described grafted sequence copolymers for the production of molded or extruded objects, films, foils, plates or the like.

Finally, the invention concerns polymer alloys comprising grafted sequence copolymers as described above and at least two polymers or resins which are incompatible with each other, at least one being compatible with the stem of the grafted sequence copolymers and at least one being compatible with the grafted polymers.

The grafted sequence copolymer can be incorporated in a conventional manner into the mixture of thermoplastic resins, in a molten state, in a conventional kneading device. The amount of copolymer introduced may be between 1 and 30%, preferably it is 2 to 15% by weight relative to the weight of the thermoplastic resin mixture.

Polyvinyl chloride, PVC and copolymers or mixtures containing vinyl chloride monomer, VCM, may be mentioned in particular as examples of thermoplastic polymers or resins compatible with the polymers from a monomer mixture containing vinyl chloride.

The following examples shall illustrate the invention.

Example 1

150 g granules of polyetheresteramide with an average particle size equal to approx. 3 mm is added to a 2 1 reactor.

The polyether ester amide used is obtained by copolycondensation of a,co-dicarboxylated polyamide 12 blocks with Mn = 600 with a,cj-dihydroxylated polytetramethylene glycol blocks with average Mn = 2,000.

After a strong vacuum has been applied for 5 minutes, 45 g of butyl acrylate and 3 g of polymerization initiator are added.

After 2 hours of gentle stirring of the reaction mixture at ■ ambient temperature, 800 g of water are added and the reaction mixture is heated to 56°C.

The polymerization takes place at 56°C for 6 hours. After the polymerization is finished, the unreacted monomers, that is, those that are neither grafted nor polymerized, are removed from the monomer mixture.

The obtained copolymers are then filtered off and then dried under vacuum. 182 g of resin granules are obtained and this is converted into test pieces by passing through an injection press.

The test pieces are assessed for stretch and elongation in accordance with NF standard T 51 034 and for Shore D hardness in accordance with ISO standard 868.

Example 2

150 g of polyetheresteramide granules with an average particle size of approx. 3 mm and characteristics identical to those described in example 1, are added to 2 1 reactor.

After a strong vacuum has been applied for 5 minutes, 45 g of methyl methacrylate and 3 g of polymerization initiator are added.

The polymerisation/grafting, filtration and drying conditions are identical to those described in example 1. 186 g of granules are obtained and this is injection molded into test pieces which are evaluated under the same conditions as in example 1.

Example 3

A. 1,600 g of polyetheresteramide powder with an average particle size equal to 40 pm is dispersed in 13 kg of water containing 18 g of stabilizer (a colloid of the polyvinyl alcohol type) in a 25 l reactor.

The polyetheresteramide has the same characteristics as that used in example 1.

A heavy vacuum was applied for 5 minutes before adding 5400 g of VCM and 32 g of polymerization initiator. The reactor is

equipped with a Pf audler stirrer and a counter blade and has a stirring speed of 300 rpm.

The reaction mixture is first stirred at ambient temperature for 2 hours and then heated under autogenous pressure to 60°C for 6 hours.

The reactor is then degassed to remove unreacted monomer.

The graft copolymers are then isolated and then formulated with formulation aids.

Sheets or foils are obtained by calendering and the whole is pressed into plates from which test pieces are cut using a punch so that they can be assessed in the same way as in example 1.

The results are summarized in Table I.

B. As a comparison, 350 g of polyetheresteramide powder with the same characteristics as under A) are mixed on a roller mill with 650 g of PVC with a viscosity index VI = 110, 10 g of heat stabilizer and 0.3 g of lubricant for 5 minutes at 170°C.

Sheets are obtained at the mill outlet and these are pressed into plates with dimensions 150 mm x 150 mm x 2 mm respectively 150 mm x 150 mm x 4 mm for 5 minutes at 200°C, from which plates test pieces are cut out using a punch and the the whole is assessed as under A).

Example 4

A. 150 g of polyetheresteramide powder is dispersed in 1,100 g of water containing 1.7 g of stabilizer in the form of a colloid of the polyvinyl alcohol type, in a 2 1 reactor.

Heavy vacuum is applied for 5 minutes before adding 280 g of VCM and 3 g of polymerization initiator.

After a period of 2 hours at 25° C with gentle stirring at 50 rpm, 900 g of water is added. The polymerization takes place at 60°C for 6 hours with stirring. 4 g of heat stabilizer, 0.9 g of lubricant and 100 g of VCM are then added. The reaction mixture is stirred for one hour at 30° C before unreacted VCM is stripped off.

The copolymers obtained are then filtered off and then dried under vacuum. 370 g of powder is thereby obtained. The conditions for converting the grafted sequence polymers into plates and the conditions for evaluating the test pieces are identical to what is stated in example 3.

B. 420 g polyetheresteramide powder, 580 g PVC with VI = 110, 10

g of heat stabilizer and 0.3 g of lubricant are mixed for 5 minutes at 170°C.

Polyetheresteramide used under A and B has the same characteristics as described in example 1. The test pieces are assessed using the same samples as described in example 1.

The results obtained are shown in Table I.

Example 5

A. 2,250 g polyetheresteramide granules with an average particle size of approx. 3 mm is added to a 25 1 reactor. After a heavy vacuum has been applied for 5 minutes, 3,150 g of VCM and 45 g of polymerization initiator are added.

The polyetheresteramide has the same characteristics as used in example 1.

After 2 hours of gentle stirring of the reaction mixture at ambient temperature, 9 kg of water is added. The reaction mixture is heated to 60°C and stirred for 6 hours. 200 g of heat stabilizer, 13 g of lubricant and 1 kg of VCM are then added. After one hour at 30° C, the reaction mixture is degassed to remove unreacted monomer. The graft copolymers are then isolated and then dried under vacuum. 4,300 g of granules are obtained and this is converted into plates from which test pieces are cut in the same way as in example 3. The test pieces are then assessed using the same samples as stated in example 3.

The results obtained under A) are listed in Table I.

B. 530 g of polyetheresteramide with the same characteristics and the same particle size as in example 3 are mixed on a roller mill with 470 g of PVC with VI = 110, 10 g of heat stabilizer and 0.3 g of lubricant for 5 minutes at 170°C.

Sheets are obtained which are pressed for 5 minutes at 200°C to give plates from which test pieces are cut and judged as under

A).

The results obtained are listed in Table I.

Example 6

100 g of polyetheresteramide powder with the same characteristics and the same particle size as described under example 3 is added to a 1 l reactor of the post-polymerization type and a heavy vacuum is applied for 15 minutes.

600 g of VCM and 1.5 g of polymerization initiator are then added.

The powdered mixture is allowed to swell for 30 minutes at rest at ambient temperature and the reactor is then heated to 60°C for 7 hours to allow polymerization/grafting to occur while stirring at 100 rpm.

The obtained 430 g of graft copolymers are formulated with tin salt as a heat stabilizer and polyethylene wax as a lubricant and the whole is calendered into the form of sheets that are pressed into plates from which the test pieces are punched and tested under conditions as indicated in example 3.

The results obtained are listed in Table I.

Example 7

2,500 g of polyetheresteramide granules with an average particle size of approx. 3 mm is added to a 25 1 reactor.

The polyether ester amide is obtained by polycondensation of a,co-dicarboxylated polyamide-12 blocks with an average molecular weight of 2,000 with polytetramethylene glycol blocks with an average molecular weight of 2,000.

After a heavy vacuum has been applied for 5 minutes, 2,500 g of VCM and 25 g of polymerization initiator are added. After 2 hours of gentle stirring of the reaction mixture at ambient temperature, 5 kg of water is added. The reaction mixture is heated to 56°C for 6 hours and then cooled to 30°C.

Then 1 kg of VCM, 200 g of heat stabilizer and 12.5 g of lubricant are added.

The whole is heated to 35°C for 2 hours, after which unreacted VCM is stripped off.

After filtering and drying, 4,300 g of granules are obtained and this is converted into plates from which test pieces are cut and judged in the same way as in example 3.

The results obtained are listed in Table I.

Example 8

150 g of polyetheresteramide granules with an average particle size of approx. 3 mm and with characteristics identical to those described in example 1, is added to a 2 1 reactor.

After a heavy vacuum is applied for 5 minutes, 200 g of VCM, 20 g of vinyl acetate and 3 g of polymerization initiator are added.

After 2 hours of gentle stirring of the reaction mixture at ambient temperature, 800 g of water are added. The reaction mixture is heated to 60°C and stirred for 6 hours. 10 g of heat stabilizer, 1 g of lubricant and 100 g of VCM are then added. After one hour at 30°C, the reaction mixture is degassed to remove unconverted monomers. The graft copolymers are then isolated and then dried under vacuum. 310 g of granules are obtained and this is converted into plates from which the test pieces are cut in the same way as in example 3. The test pieces are then assessed using the same tests as described in example 3.

The results are combined in Table I.

Example 9

150 g of polyetheresteramide granules with an average particle size of approx. 3 mm and with characteristics identical to those described in example 1, are added to 2 1 reactor.

After a heavy vacuum has been applied for 5 minutes, 45 g of styrene and 3 g of polymerization initiator are added.

Polymerization/grafting, filtration and drying take place in the same way as described in example 1. 182 g of granules are obtained in this way and this is injection molded into the form of test pieces which are evaluated under the same conditions as stated in example 1.

The results are summarized in Table I.

Example 10

150 g of polyetheresteramide granules with an average particle size of approx. 3 mm and with characteristics identical to those described in example 1, is added to a 2 1 reactor.

After a heavy vacuum has been applied for 5 minutes, 150 g of styrene and 3 g of polymerization initiator are added.

The conditions for polymerisation/grafting, filtering and drying are identical to those described in example 1. 300 g of granules are obtained and this is injection molded in the form of test pieces which are assessed under the same conditions as in example 1.

The results are combined in Table I.

Example 11

150 g of polyetheresteramide granules with an average particle size of approx. 3 mm and with characteristics identical to those described in example 1, is added to a 2 1 reactor.

After a heavy vacuum has been applied for 5 minutes, 160 g of 2-ethylhexyl acrylate and 3 g of polymerization initiator are added.

The conditions for polymerisation/grafting, filtering and drying are identical to those described in example 1. 300 g of granules are obtained and this is injection molded into the form of test pieces which are assessed as in example 1.

The results are listed in Table I.

Example 12

150 g of polyetheresteramide granules with an average particle size of approx. 3 mm and with characteristics identical to those described in example 1, is added to a 2 1 reactor.

After a heavy vacuum has been applied for 5 minutes, 150 g of trichlorotrifluoroethylene and 2 g of polymerization initiator are added.

The conditions for polymerisation/grafting, filtering and drying are identical to those described in example 1. 255 g of granules are obtained and this is injection molded into test pieces which are assessed under the same conditions as in example 1.

The results are summarized in Table I.

Example 13

150 g of polyether ester granules with an average particle size of approx. 3 mm is added to a 2 1 reactor. The polyether ester that was used is obtained by copolymerizing polytetramethylene glycol blocks with a molecular weight of 2,000 with polyester blocks consisting of polybutylene terephthalate. The Shore D hardness is equal to 35.

After a heavy vacuum has been applied for 5 minutes, 45 g of butyl acrylate and 3 g of polymerization initiator are added.

The conditions for polymerisation/grafting, filtering and drying are identical to those described in example 1. 188 g of granules are obtained in this way and this is injection molded into the form of test pieces which are assessed under the same conditions as in example 1.

The results are combined in Table I.

Example 14

150 g of polyetherester granules with an average particle size of approx. 3 mm and with characteristics identical to those described in example 13, is added to a 2 1 reactor.

After a heavy vacuum has been applied for 5 minutes, 45 g of methyl methacrylate and 3 g of polymerization initiator are added. The conditions for polymerisation/grafting, filtering and drying are identical to those described in example 1. In this way, 189 g of granules are obtained and this is injection molded into the form of test pieces which are then assessed under the same conditions as in example 1.

The results are combined in Table I.

Example 15

150 g of polyetherester granules with an average particle size of approx. 3 mm and with characteristics identical to those described in example 13, is added to a 2 1 reactor.

After a heavy vacuum has been applied for 5 minutes, 200 g of VCM and 3 g of polymerization initiator are added.

The conditions for polymerisation/grafting are identical to those described in example 8. Before stripping unconverted VCM, 10 g of tin salt are added as a heat stabilizer and 1 g of polyethylene wax as a lubricant.

186 g of granules are obtained and this is injection molded into the form of test pieces which are then assessed under the same conditions as in example 1.

The results are combined in Table I.

Example 16

150 g of polyetherester granules with an average particle size of approx. 3 mm and with characteristics identical to those described in example 13, is added to a 2 1 reactor.

After a heavy vacuum has been applied for 5 minutes, 45 g of styrene and 3 g of polymerization initiator are added.

The conditions for polymerisation/grafting, filtration and the drying conditions are identical to those described in example 1. 183 g of granules are obtained and this is injection molded into the form of test pieces which are assessed under the same conditions as in example 1.

The results are combined in Table I.

Example 17 (Comparison)

A. Sheets of two types of polyetheresteramide are cast, one with the same characteristics as those found in example 1, sample A^, the other with the same characteristics as used in example 7, sample A2 •

B. Sheets of PVC, softened with diisooctyl phthalate, are cast

(softened with 40 phh; sample B^ )

(softened with 60 phh; sample Bg)

(softened with 100 phh; sample B3)

(phh means per 100 g resin).

C. Polyetherester sheets are cast (these have the same

characteristics such as those in example 13).

Test pieces are cut from the plates obtained under A, B and C and these are tested under the conditions described in example 1.

The results are combined in Table I.

Claims (9)

1. Grafted sequence copolymers whose stem, based on polyether polyester amides, consists of block polyester or block polyamide parts, distributed sequentially, characterized by) that at least one sequence of the stem is soluble in the monomer mixture from which the grafting originates and that at least one sequence of the stem is insoluble in the monomer mixture, and ii) that the grafts are made with vinyl chloride, vinylidene chloride, chlorotrifluoroethylene, methyl, ethyl, butyl or 2-ethylhexyl (meth)acrylate, styrene, α-methylstyrene or vinyl acetate. 2. Grafted sequence copolymers according to claim 1, characterized in that they are formed from one to 99.9% by weight of grafted polymers, preferably 10 to 99.9%. 3. Grafted sequence copolymers according to claims 1 and 2, characterized in that the stems are based on polyester blocks and polyether blocks. 4. Process for producing grafted sequence copolymers as specified in claims 1 to 3, characterized in that radical grafting of the monomer mixture and radical polymerization of the stem is carried out. 5 . Method according to claim 4, characterized in that the polymerization/grafting is carried out in suspension. 6. Method according to claim 4, characterized in that the polymerization/grafting takes place in bulk. 7. Use of grafted sequence copolymers as stated in claims 1 to 4 for the production of molded or extruded objects, films, foils, plates or the like. 8. Polymer alloy comprising grafted sequence copolymers according to claims 1 to 3 and at least two polymers or resins which are incompatible with each other, in that at least one is compatible with the stem of the grafted sequence copolymers and at least one is compatible with the grafted polymers. 9. Polymer alloy according to claim 8, characterized in that it contains 1 to 30 wt # of grafted sequence copolymers as stated in claims 1 to 4, preferably 2 to 15 io, calculated on the weight of the mixture of polymers or resins.