SK78194A3 - Polyvinylchloride ready for processing and its preparation method - Google Patents

Abstract

The invention relates to a homo- or copolymer composition of a vinyl chloride, which is ready for processing and which contains additives necessary from the point of view of the processing, such as stabilizers, lubricants, colourants, reinforcing agents and processing aids, and to a method for its preparation. The polymer has been prepared by adding into the polymerization reactor in the beginning of the polymerization, during it or at the end thereof 0.01-50 weight-% of the amount of vinyl chloride a liquid olefin oligomer and/or ethylene olefin copolymer or olefin terpolymer.

Description

Processable polyvinyl chloride and process for its preparation

Technical field

The invention relates to vinyl chloride which is directly prepared for processing and in which the necessary additives such as stabilizers, lubricants, dyes and reinforcing agents and the like are added to the polymer in the polymerization reactor. The invention also relates to a process for the preparation of such a vinyl chloride polymer.

BACKGROUND OF THE INVENTION

Polyvinyl chloride is an economically valuable thermoplastic suitable for various applications. To make the polyvinyl chloride (PVC) suitable for processing, one or more stabilizers, lubricants, pigments and / or modifiers are added to the polymer obtained by polymerization. From the point of view of the PVC product manufacturer, it would be necessary for the purchased polymer to be as ready as possible for further processing. At present, it is necessary to provide a separate mixing device downstream of the polymerization reactor or in the plant of the final product processor. Research has been carried out on the addition of additives, especially stabilizers, during the polymerization reaction, and some published documents are also available on this subject.

U.S. Pat. No. 3862066 discloses a process for the suspension polymerization of vinyl chloride in which various additives such as stabilizers, lubricants, pigments and the like are added to the polymerization reactor at the beginning or during the polymerization reaction. At the end of the polymerization reaction, an inhibitor is added to stop the polymerization reaction to obtain the desired degree of conversion.

In the published patent application DE 3630318 a specific type of polyoxazoline is used as a suspension stabilizer by means of which organic or inorganic zinc compounds can be added to the polymerization reactor as a stabilizer. Subsequent final stabilization is carried out in the usual manner.

According to published patent application GB 1577030, additives are introduced into the polymerization reactor in conjunction with the bulk polymerization of vinyl chloride. According to this application, conventional additives can be used. The polymerization reaction may take the form of a two-stage polymerization reaction, with the additives being added in the second step. Thus, for example, stabilizers, lubricants and processing aids are added.

As far as we know, these currently known processes are not successfully used on an industrial scale, as production processes in which a polymer suitable for direct processing are obtained by means of a polymerization reaction are not yet used. In the experiments leading to the invention, the addition of polyvinyl chloride additives to the polymerization reactor was investigated using the above-mentioned patent applications. However, it was found that they were not suitable for use. To a large extent, a waste product was formed which was lumpy or adhered to the reactor wall. The waxy lubricants used in the above-mentioned patent applications interfered with the formation of the dispersion in the reactor.

SUMMARY OF THE INVENTION

In the context of the invention, it has been found that the addition of PVC additives is possible when certain carriers are simultaneously added to the polymerization reactor. Accordingly, the homo- or copolymer compositions are characterized by being prepared by adding 0.01-50% by weight, based on the weight of vinyl chloride, a liquid olefin oligomer and / or an ethylene-olefin copolymer or olefin terpolymer, to the polymerization reactor at the start of the polymerization reaction. during or after its completion.

The liquid olefin oligomer may be a dimer, a trimer, a tetramer, a pentamer or a hexamer of α-olefins or internal olefins (carbon number 4-30), or mixtures thereof, with carbon chain lengths of 20-100 (C ₂ q-C ^ qq) . The oligomer may contain double bonds or may be hydrated.

Optionally, a liquid polymer may be used, which is an elastomeric polymer of ethylene propylene in which dicyclopentadiene or ethylidenenorbornene is used as a thermonomer. The liquid polymer may be used in addition to or instead of the oligomer. The choice of oligomer and / or liquid polymer depends on the desired properties of the final product. The addition of the liquid oligomer and / or polymer to the polymerization reactor thus makes it possible to add other additives at the beginning or during the polymerization reaction, whereby a product capable of being processed directly is obtained as a product.

The direct processing polymers of vinyl chloride prepared according to the invention can be used to produce the same products as are made from compounds prepared by conventional polymerization methods and blending techniques. The products can be manufactured by extrusion, injection molding, extrusion blow molding or calendering. Various products can be prepared, such as pipes, pipe fittings, plates, profiles, bottles.

The use of suitable additives is the same as in the preparation

I of the conventional mixture. Lead stabilizers such as lead sulphate, lead phosphite, lead carbonate or lead phthalate or barium zinc, calcium zinc compounds or tin compounds may be used as stabilizers. Lead, calcium, or zinc stearates, epoxidized soybean oils, epoxidized linseed oils or epoxidized fatty acid esters can be used as co-stabilizers.

Calcium carbonates, kaolin, silica or aluminum hydroxide can be used as fillers.

Suitable flame retardants are, for example, antimony trioxide, zinc borate, zinc oxide or aluminum hydroxide.

For example, lead, calcium or zinc stearates, fatty acids, fatty acid esters, fatty acid alcohols or fatty acid amides, natural wax, paraffin waxes, hydrocarbon waxes or polyethylene waxes may be used as external lubricants.

Suitable dyes are carbon black, titanium dioxide, various organic and inorganic pigments.

Suitable processing aids are, for example, polymethyl methacrylate and various polymers such as acrylonitrile-butadiene-styrene (ABS), methacrylate-butadiene-styrene (MBS), chlorinated polyethylene (CPE), ethylene-vinyl acetate (EVA) and various acrylate plastics.

The polymerization proceeds in a similar manner to conventional PVC preparation by the suspension polymerization method. Vinyl chloride is dispersed in water using, for example, polyvinyl alcohol (PVA) or cellulose derivatives as a suspending agent. The initiator of the polymerization reaction is an organic peroxide soluble in the monomer. Depending on the properties of the product, the polymerization temperature is in the range of 50 ° -70 ° C, which corresponds to a pressure of 0.7-1.2 MPa. The polymerization time is usually 4 to 8 hours. The polymer chain length is almost entirely determined by the temperature at which the polymerization takes place. At the final stage of the polymerization reaction, the polymerization pressure begins to decrease. After the polymerization pressure has dropped to the desired value, the reactor contents are transferred to a degassing or stripping tank in which the unpolymerized monomer is recovered and returned to the process.

• After stripping, the PVC / water mixture is dried, some of the water is removed mechanically, the residue is evaporated and finally the product is screened.

The inventive polymerization process differs from conventional processes mainly in that the oligomer and / or the liquid polymer as well as the additives are introduced into the polymerization reactor, in one or more stages at the beginning of the polymerization reaction, during or after it, while in conventional processes are admixed separately only after the polymerization reaction is complete.

Using the inventive process for polymerizing vinyl chloride, a number of advantages are achieved over the known process. Compared to the preparation of a conventional blend in which the additive to the polymer is dry blended prior to processing, according to the inventive method, a more homogeneous distribution of the additives already present at the polymerization stage is ensured. The additives can be introduced into the polymerization reactor in the form of an aqueous solution or suspension, thereby avoiding the dusting problems of the product occurring during conventional mixing processes.

The rapid pressure drop results in an increase in the degree of polymerization at high conversions, thereby decreasing the total polymerization reaction time and obtaining a higher degree of conversion.

If heat decomposition stabilizers have been added to the polymer prior to stripping, more stringent stripping conditions can be maintained in the batch stripping apparatus. The problems related to monomer emissions to air and waste water are improved, while the raw material balance is also improved. Dyeing and thermal decomposition during stripping are completely eliminated.

The drying economy can be improved by using a higher inlet temperature and a higher temperature difference. Energy consumption decreases because of improved thermal efficiency. Thermal decomposition of the polymer during drying can also be removed at temperatures higher than ΙΟΟθΟ, as heat decomposition stabilizers have already been added during the polymerization reaction.

Owing to the presence of metal-containing additives, the occurrence of static electricity is reduced, as a result of which smaller mesh sieves can be used and thus more intensive screening on the sieves.

Due to the higher density and higher granulometry, the flowability of the final polymer is better. This reduces the dusting problems of the final polymer.

If heavy metals such as lead are used for stabilization, their content (in% by weight) may be reduced for better distribution.

Most often, conventional lubricants are not required and the need for lubrication is substantially reduced, which is particularly advantageous from an economic point of view in the context of the extrusion and injection molding method.

The invention will now be described in more detail with reference to the following non-limiting examples, which are not to be construed as limiting the scope of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The polymerization reactions are carried out in an autoclave-type polymerization reactor. Standard methods were used for the analysis: bulk density: ISO R 60, viscosity number and K value: ISO R 174 and plasticizer absorption (DOP): ISO 4608.

Examples 1-5

10 kg of vinyl chloride and 15 kg of water were charged into the polymerization reactor. Calcium stearate and lead sulfate or zinc stearate were added to the reactor for stabilization. At the beginning and during the polymerization reaction, polyvinyl alcohol was added as a dispersant.

Lauryl peroxide was also added to the reaction initiator -diethylperoxide carbonate. The oligomer used was a hydrated decene oligomer, which mainly contained a tetramer (C ₄ q) and to some extent also a trimer (C 4 q) and a pentamer (C 4 q). The composition of the polymerization mixture is shown in Table 1 and the results of the polymerization in Table 2.

Table 1. Composition of the polymerization mixture

Chemicals content in g / kg vinyl chloride.

At- oligo stearate sulphate stearate initiators PVA Sodium EXAMPLE mer limes. lead. of zinc. tor peroxide 1 7.5 5 5 1.1 1.65 0.2 2 7.5 5 10 1.4 1.65 0.5 3 5.0 7.5 10 1.3 1.70 0.5 4 7.5 10 8 1.25 1.75 - 5 7.5 10 4 1.25 1.75 -

Table 2. Polymerization results

Example conversion (%) Polymerization time (min) Volume weight (G / D Granule size (D50, ^ m) porosity (%) 1 81.8 249 525 136 22.9 2 79.9 228 533 136 23.3 3 79.3 260 577 170 20.2 4 75.3 220 562 157 23.8 5 73.7 257 560 170 22.9

Examples 6-9

10 kg of vinyl chloride (VCM) and 15 kg of water were charged into the polymerization reactor. Calcium stearate and lead sulfate were also added for stabilization. The dispersant (PVA) was added at the beginning and during the polymerization reaction. In addition to the initiator -diethylperoxide carbonate, cumylperoxyneodecanoate was also used as a co-catalyst. At the beginning of the polymerization reaction, an oligomer and / or a liquid polymer of ethylene propylene (EP) was added. The hydrated oligomer used was a mixture of tetramer ^and pentamer ((59) ^{and a} liquid polymer in Example 6, an ethylene-propylene-dicyclopentadiene in Example 7, an ethylene-propylene-norbornene terpolymer in Example 8 and an ethylene-propylene copolymer in Example 9. listed in Table 4.

Table 3. Composition of the polymerization mixture

The chemical content is given in g / kg vinyl chloride.

Example E-P oligomer Lime stearate. Lead sulphate. initiator PVA Auxiliary catalyst. 6 7.5 7.5 20 1.3 2.05 0.2 7 7 7.05 10 15 1.3 2.05 0.5 8 12 - 4 15 1.3 1.85 - 9 2.1 4.9 5 12 1.5 1.28

Table 4. Polymerization results

Example conversion (%) Polymerization time (min) 0bj Density (g / 1) Granule size (D50, y ^ m) porosity (%) 6 73,4 248 566 167 21.8 7 71.2 224 558 151 22.76 8 81.3 418 583 172 19.9 9 87.8 243 575 170 25.7

Examples 10-12

Industrial-scale polymerizations were carried out in conventional polymerization reactors by the same techniques as in standard PVC preparation. However, during the polymerization reaction, an olefin oligomer and / or an ethylene propylene liquid copolymer was added like the other additives. A conventional polymer having a K value of 68 was used as the comparative polymer. Standard methods were used in the analysis of the polymers and in the testing of the samples made of the polymers. The additives used are listed in Table 5 and the ratio analysis in Table 6.

Table 5. Additives used

Example 10 11 12 Oligomer (%) 0.8 0.8 0.3 Ethylene-propylene copolymer (%) - - 0.7 Calcium stearate (%) 1.0 1.0 0.9 Zinc stearate (%) 0.8 0.4 - Lead sulphate - - 1.2 Epoxy Soya Oil (%) 3.0 0.8 0.2

Table 6. Polymer analyzes

Example 10 11 12 S-116 Bulk density (kg / m ^) 498 499 556 560 Softener Absorption (DOP) (%) 24.0 25.3 24.5 21.0 Viscosity number 107.4 112.4 114.0 116.0 K value 65.6 67.0 67.4 67.9 Particle size, D50, (jun) 160 166 131 165

Example 13

Extrusion of polymer pipes of Examples 10 and 11:

The tubes (110 / 3.2mm) were made of polymers with a CM65 twin screw extruder. Thread pitch: diameter 65 / 120mm, length 1210 mm, operating speed: 34.4 οΐ / min, total torsion: 10.2 kNm.

Impact tests were performed on the tubes using the standard SS3064 method. In this case the weight of the weight was 6.0 kg and the diameter of the drop weight was 25 mm. The tubes were maintained at -10 or -20 ° C for 24 hours prior to the impact test. The comparative polymer was a vinyl chloride polymer produced in a conventional manner. Stabilizers were dry blended into the comparative polymer. The results of the impact test are shown in Table 7. From the results it can be seen that the polymer prepared according to the invention is very good for impact toughness and that the tubes made therefrom are also very suitable for use in cold conditions.

Table 7. Impact test results

Compare the polymer Example 10 Example 1; -10 ° C / 24 hr 162 cm 185 cm 212 cm -20 ° C / 24 hr 81 cm 194 črr 209 cm Examples 14 - 15

The polymerizations were carried out under the same conditions and using the same methods as described in Example 2 of U.S. Pat. 3,862,066th

When the paraffin wax and stearamide used as a lubricant in the above-mentioned patent were replaced by an olefin oligomer that was a mixture of tetramer (C1-4) and pentamer (C1-4) decene, the corresponding polymer was obtained. This polymer was still quite coarse while the waste products were not obtained. Paraffin wax is disclosed in U.S. Pat. 3862066 did not dissolve, thereby disturbing the dispersion. The polymerizations were carried out in an autoclave type polymerization reactor in which 1250 kg of vinyl chloride and 1850 kg of water were charged. The additives used are shown in Table 8 and the analysis of the polymers in Table 9.

Example 14 Example 15 oligomer 15 VAX-C 11.8 - IRGAVAX 367 8 - Calcium carbonate 20 20 Calcium stearate 11.8 11.8 Titanium dioxide 15.9 15.9 Epoxized soybean oil 12 12 NOPCO NXZ (antifoam) 0.8 0.8

Table 9. Polymer analyzes

Example 14 Example 15 a Bulk density (kg / m ^a ) 501 623 Porosity (DOP) (%) 40.3 18.4 Particle size, D50, (^ * m) 318 289 Waste product (% / VC) 17.8 6.3

Examples 16-19

13 kg of vinyl chloride, 15.6 kg of water and a total of 1.4 kg of polyvinyl alcohol as dispersant per kg of VCM (vinyl chloride monomer) were charged into the polymerization reactor. 1.3 g / kg of VCM dicetyl peroxide carbonate was used as initiator. At the beginning of the polymerization, 10 g / kg of VCM lead sulfate was introduced. The oligomer used was a hydrated decene oligomer containing tetramers (C4Q), pentamers (C1-4), and heptamers (Cyg). Oligomer added:

Example 16: - at the start of the polymerization reaction Example 17: - during the polymerization reaction, 40 min. after its start

Example 18: - during the reaction prior to depressurization, Example 19: - to the suspension after gas removal.

Table 8. Polymerization and analysis of polymers

Example conversion (%) Polymerization time (min) 0bj Density (g / D Granule size (D50, ^ m) DOP (%) 16 92 261 505 179 21.6 17 92 272 524 182 20.9 18 88 301 498 180 19.1 19 88 303 512 192 21.6

Example 20

The polymerization reaction proceeded in the same manner as in Example 16, but the oligomer used was a mixture of internal olefins containing 90% olefin C18 and 10% olefin. The oligomer contained 47% dimers, 40% trimers and 13% tetramers. Results of the polymerization reaction:

Claims (13)

1. A homo- or copolymer of vinyl chloride which is capable of being directly processed and which contains the necessary impurities such as stabilizers, lubricants, colorants, reinforcing agents and processing agents, characterized in that it is prepared by the addition of 0,01 50% by weight; based on the weight of vinyl chloride, liquid olefin oligomer and / or ethylene-olefin copolymer or olefin terpolymer into the polymerization reactor at the beginning, during or at the end of the polymerization reaction. 2. The polymer of claim 1, wherein the vinyl chloride polymer has been prepared by the slurry polymerization method. Polymer according to claim 1, characterized in that the oligomer is preferably a dimer, trimer, tetramer, pentamer or hexamer of an α-olefin containing 4-30 carbon atoms or an internal olefin or a mixture thereof. The polymer of claim 1, wherein the oligomer is most preferably an α-olefin containing 8-14 carbon atoms, wherein the carbon chain contains 16,100 carbon atoms. Polymer according to claim 1, characterized in that the liquid olefin polymer is preferably an ethylene-propylene copolymer. Polymer according to claim 1, characterized in that the liquid olefin polymer is preferably an ethylene-propylene-diene terpolymer. The polymer of claim 1, wherein the liquid olefin polymer is most preferably an ethylene-propylene-dicyclopentadiene terpolymer or ethylene-propylene-ethylidene-norbornene. 8. A process for the preparation of a homo- or copolymer of vinyl chloride which is capable of being directly processed and which contains the necessary additives for processing, such as stabilizers, lubricants, colorants, reinforcing agents and processing agents, characterized in that it is added to the polymerization reactor. start, during or at the end of the polymerization reaction 0.01 - 50% by weight, based on the weight of the vinyl chloride, the liquid olefin oligomer and / or the ethylene-olefin copolymer or olefin terpolymer. Polymer according to claim 8, characterized in that the oligomer is preferably a dimer, a trimer, a tetramer, a pentamer or a hexamer of α-olefin containing 4-30 carbon atoms or an internal olefin or a mixture thereof. • Process according to either of Claims 8 and 9, characterized in that the oligomer is most preferably an α-olefin containing 8-14 carbon atoms, the carbon chain comprising 16-100 carbon atoms. Process according to Claim 8, characterized in that the liquid olefin polymer is preferably an ethylene-propylene copolymer. Process according to Claim 8, characterized in that the liquid olefin polymer is preferably an ethylene-propylene-diene terpolymer. Process according to Claim 8, characterized in that the liquid olefin polymer is most preferably ethylene-propylene-dicyclopentadiene terpolymer or ethylene-propylene-ethylidene-norbornene.