FI95474C - Vinyl chloride polymer - Google Patents

Description

5 95474

vinyl chloride

Vinylkloridpolymer

The invention relates to a homo- or copolymer of vinyl chloride.

Polyvinyl chloride (PVC) is a low-cost thermoplastic suitable for many applications. In order for PVC to be suitable for processing, various additives such as stabilizers, lubricants, pigments and / or modifiers are usually added to the resin obtained from the polymerization. The additives are usually mixed with the PVC polymer only afterwards before use.

Methods are also known in which, in connection with PVC polymerization, monomers or polymers which improve the properties of the final product or regulate the polymerization of vinyl chloride are added to the polymerization reactor. Thus, for example, according to U.S. Pat. No. 3,560,462, at least one C10-C22 alpha-olefin, preferably hexadecene or octadecene, has been added to the vinyl chloride polymerization reactor to prevent self-acceleration of the polymerization reaction. The amount of alpha-olefin is 0.1-5% by weight.

Patent application JP 61155401 discloses a suspension polymerization process in which 0.1-5% of C6-C20 alpha-olefin is copolymerized with vinyl chloride. Polymer 25 has a lower than usual residual monomer content and fewer fish eyes.

U.S. Pat. No. 4,031,299 discloses the suspension polymerization of vinyl chloride. a process in which a pre-homogenized polyallyl compound and a propylene oligomer, preferably a tetramer, are added to the polymerization reactor. The propylene oligomer 30 can be used to improve rheological properties.

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In patent application JP 51059987, vinyl chloride is polymerized to reduce the number of fish eyes present in the polymer in the presence of low molecular weight polyethylene and an alkane and / or fatty acid ester.

According to the invention, it has been found that improved homopolymers or copolymers of vinyl chloride are obtained if the polymer contains longer carbon chain alpha-olefins as oligomers. Thus, a homo- or copolymer of vinyl chloride according to the invention is characterized in that it contains 0.01-50% of an oligomer of a C4-C20 alpha-olefin or an internal olefin or mixtures thereof, and that the oligomer is added to the polymerization reactor 10 at the beginning or during the polymerization.

In the vinyl chloride polymer of the invention, the alpha-olefin oligomer is likely to act as an internal lubricant, which reduces or eliminates the need for other conventionally used lubricants and other excipients.

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The oligomer may be added to the polymerization reactor at the beginning of the polymerization or later during the polymerization or after the polymerization reaction. In some applications, the oligomer can also be added to the finished polymer by mixing to act like a conventional lubricant.

20

In the vinyl chloride polymer according to the invention, when the oligomer is added to the rector during the polymerization in the polymerization reactor, it is made to mix easily with the uniformly formed polymer. This allows good product properties and processing of polyvinyl chloride without the addition of other lubricants or it reduces the need for 25 other lubricants. The need for other additives is also lower and the mechanical properties of the product are better than conventionally produced PVC. The polyvinyl chloride prepared according to the invention can be used for the same applications as those prepared by conventional methods.

The oligomer contained in the homo- or copolymer of vinyl chloride of the present invention may be prepared from C4-C20 alpha-olefins or internal olefins or mixtures thereof. Thus, suitable olefins are butenes, pentenes, 3 95474 hexenes, octenes, heptenes, decenes, etc. Highly suitable are C8-C14 olefins and particularly suitable decenes such as 1-decene, 1-dodecene, 1-hexadecene and 1-tetradecene.

The oligomer used in the polymers according to the invention may be a dimer, a trimer, a tetramer, a pentamer or a hexamer or a mixture thereof, i.e. the length of the carbon chain is preferably between Cgg-C2. The oligomers may contain reactive double bonds or may be hydrogenated. The type of oligomer most suitable depends on the application of the polymer.

10

The polymerization is carried out by any conventional method of polymerizing vinyl chloride, but most commonly by suspension polymerization. The polymerization takes place as a batch process in a reactor equipped with a stirrer, the contents of which can be heated or cooled with water flowing in the jacket. The composition of the polymerization mixture is typically as follows: water 120-200 parts by weight, vinyl chloride monomer 100 parts by weight, suspending agent 0.05-0.15 parts by weight and vinyl chloride soluble initiator 0.03-0.07 parts by weight. The reactor containing the monomer, with the exception of the other components of the mixture, is evacuated and vinyl chloride is added to the mixture. Thanks to efficient mixing, it is divided into 20 water into small droplets with a diameter of 50-150 μm. A suspending agent such as polyvinyl alcohol stabilizes the mixture. The polymerization begins in the monomer droplets when the temperature is raised to 50 ° C, after which the temperature is adjusted as desired (50-75 ° C). The charge is transferred to degassing and stripping tanks. The monomer remaining in the polymer particles is removed by steam stripping. The mixture is centrifuged and the solid is usually dried by fluid bed or drum method.

The molecular weight of PVC is controlled by the polymerization temperature, as the temperature increases, the size of the polymer molecules decreases. Similarly, the porosity of the particles depends on the temperature; as it rises, the porosity decreases.

Azo or peroxide compounds such as diacetyl peroxides, peroxide carbonates, alkyl peroxide esters or azodiisobutylnitrile are used as initiators in the polymerization of vinyl chloride. The rate of polymerization depends on the initiator. For example, layyl peroxide and azodiisobutylnitrile are best used at higher polymerization temperatures, while more readily degradable compounds such as acetylcyclohexylsulfonyl peroxide or di-2-ethylhexyl peroxydicarbonate are suitable for lower temperatures. In many cases, it is preferable to use a mixture of the two initiators. The total polymerization time is usually 4 to 10 hours.

Polyvinyl alcohol or cellulose derivatives such as methyl, hydroxyethyl, hydroxypropylmethyl or hydroxypropylcellulose or mixtures thereof are used as suspending (dispersing) agents. Some of the dispersant is often added later during the polymerization.

Hydrochloric acid formed from vinyl chloride during polymerization and acids formed from some initiators are neutralized with bases or buffering compounds such as sodium or magnesium hydroxide or carbonate.

Prior to processing, the necessary additives are mixed into the polymer.

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The following non-limiting examples illustrate the invention:

Laboratory scale polymerizations were performed in an autoclave type polymerization reactor. The standard method used for the analysis is: bulk density: ISO R 25 60, viscosity number and K-value: ISO R 174 and plasticizer absorption (DOP) ISO

4608.

Examples 1-4 To the polymerization reactor were added 10 kg of vinyl chloride monomer (VCM), 12 kg of water and polyvinyl alcohol 0.57 g / kg VCM as a dispersant. Dispersant was added during the polymerization at 0.7 g / kg VCM. Dimethyl peroxide carbonate was used as the initiator. The oligomer was added to the polymerization reactor at the beginning of the polymerization. As the oligomer, a double-bonded decene oligomer containing mainly a trimer (C4q) and a tetramer (C4Q) was used. The polymerization temperature was 57 ° C. The polymerization experiments are shown in Table 5 1.

Table 1. Polymerizations

Example oligomer initiator conversion polymerization 10 g / kg VCM g / kg VCM% total time, min 1 10 2.0 69.6 251 2 20 2.0 57.3 357 3 35 2.5 45.1 426 15 4 100 2, 5 56.5 779

The properties of the polymers are shown in Table 2.

20 Table 2. Resin analyzes

Example Bulk density Grain size K value Viscosity DOP g / 1 D50, μm% 25 _ 1,575,170 66.3 110 20 2,586,134 65.3 107 18 3,549,139 62.6 97.0 19.7 4,464,129 54 , 6 72.6 26.8 30 _ 6 95474

Examples 5 and 6

The polymerizations were carried out in the same manner, but a hydrogenated decene oligomer containing mainly a tetramer (C4Q) but also a trimer (Cgg) and a pentamer (Cgg) was used as the oligomer. Initiator 1.25 g / kg VCM. The polymerizations are shown in Table 3 and the resin analyzes in Table 4.

Table 3. Polymerizations 10

Example oligomer conversion polymerization time g / kg VCM% min 15 5 10 67.6 261 6 15 59.0 255

Table 4. Resin analyzes 20

Example Bulk density Grain size DOP g / l D50, pm% 25 5 557 178 20.7 6 565 162 20.5

Examples 7-9

The autoclave-type polymerization reactor was charged with 1450 g of vinyl chloride and 1740 g of water. A total of 1.5 g / kg VCM poly- 30 was used as dispersant

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vinyl alcohol. The initiator was disethyl peroxydicarbonate. As the oligomer, a hydrogenated decene oligomer containing mainly tetramer (C40) and pentamer (C4g) was used. The polymerization conditions are shown in Table 5 and the resin analyzes in Table 6. Such oligomer-rich polyvinyl-5 chloride can be used, for example, in a mixing plant to control the lubrication level of low oligomer or conventional PVC.

Table 5. Polymerizations 10

Example oligomer initiation conversion g / kg VCM g / kg VCM% total time, min 7,200 1.8 88.5 305 15 8 300 1.8 84.1 480 9 500 1.5 78.7 480

Table 6. Resin analyzes 20

Example Bulk density Grain size DOP

g / l D50, Jim% 25 7 558 125 15.8 8 545 166 16.9 9 470 199 20.5 30 Examples 10-14

Stabilized blends were made from the resins obtained in the polymerizations. In all 8 95474 examples, 100 parts by weight of polyvinyl chloride, 1 part by weight of lead sulphate and 0.2 parts by weight of stearic acid were used. Thermal stability (Congo red) was determined according to the ISO R 182 method and the VICAT softening point according to the ISO R 306 method. MS pressure refers to a gelation test with a Maclow-Smith plastometer 5. The results are shown in Table 7.

Table 7. Mixture properties

10 Example Oligomer amount MS pressure Congo red VICAT g / kg VCM kg / cm2 s ° C

10 - 182 100 84 H 10 161 180 79 15 12 20 110 180 78.5 13 30 100 210 77 14 100 42 280 76.5 20 It is clear from the results that the addition of the oligomer significantly improves the thermal stability. The lubricant properties of the oligomer appear at MS pressure, i.e. the machining properties are better than with conventional PVC.

25 9 95474

Example 15

13 kg of vinyl chloride monomer (VCM), 15.6 kg of water and a total of 1.4 kg of polyvinyl alcohol / kg of VCM were dispersed in the polymerization reactor. Dimethyl peroxide carbonate 1.3 kg / kg VCM was used as initiator. The oligomer used was a mixture of internal olefins containing 90% C15 olefin and 10% C16 olefin. The oligomer contained 48% dimers, 39% trimers and 13% tetramers. The polymerization results were: 10 Conversion 91%

Polymerization time 342 min

Bulk density 548 1 / kg

Grain size, D50 182 μτη

Plasticizer absorption 20.8% 15

Claims (7)

95474 A homopolymer or copolymer of vinyl chloride, characterized in that it contains 0.01-50% of an oligomer of a C4-C20 alpha-olefin or an internal olefin or mixtures thereof, and that the oligomer is added to the polymerization reactor at the beginning or during the polymerization. Polymer according to Claim 1, characterized in that the oligomer is an oligomer of a C 8 -C 14 alpha-olefin. Polymer according to Claim 1 or 2, characterized in that the oligomer contains dimers, trimers, tetramers, pentamers or hexamers or mixtures thereof. Polymer according to one of the preceding claims, characterized in that the oligomer contains double bonds. Polymer according to Claim 4, characterized in that the double bonds of the oligomer are hydrogenated. 20 Polymer according to one of the preceding claims, characterized in that the polymer is prepared by a suspension polymerization process. Polymer according to one of the preceding claims, characterized in that the alpha-olefin is 1-decene. I m. ». ·, United lii» i 95474