FI57768C - EXPANDER BAR STYRENPOLYMER SOM LAEMPAR SIG FOER FRAMSTAELLNING AV UR FORMARNA SNABBT UTTAGBARA CELLFORMKROPPAR - Google Patents

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Federal Republic of Germany Förbundsrepubliken lyskland (DE) P 2255397-5 (71) Chemische Werke Hiils Aktiengesellschaft, Kreis Recklinghausen, 1 + 370 Marl, Federal Republic of Germany Förbundsrepubliken Germany (DE) (72) Rudolf de Jong, German Republic (DE) (7U) Oy Jalo Ant-Wuorinen Ab.

(5U) The present invention relates to expandable styrene polymers which are suitable for the production of a compound which is soluble in the monomeric styrene and which forms a discontinuous phase with the styrene polymers.

It is known to make foamed shaped bodies by expanding fluffable fine styrene polymers in molds.

According to this method, the finely divided inflatable styrene polymers are first subjected to a so-called pre-foaming process by means of water vapor or hot gases. The pre-foamed particles are then stored and further foamed in perforated molds with hot steam and sintered. After this so-called final foaming, the shaped body must remain in the mold for a short time until it has cooled so much that it can be removed from the mold without any deformation. This residence time in the mold, also called the cooling time, is the "dead" time that is sought to be kept as short as possible in order to make better use of the molds.

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A number of methods are known which make it possible to shorten cooling times and thus obtain moldings which can be removed more quickly from molds, for example by coating expandable or pre-foamed particles with paraffin oil (DT application 1 569 162, DT publication 1 959 729) or oil lubricant application publication 1 769 549). In addition, rapidly removable cell shaped bodies are obtained from the molds. The expandable particles contain small amounts of water in the finely divided form obtained from their manufacture (DT Hacking Publication No. 1,719,318) or when the expandable particles are prepared by polymerization using small amounts of certain bromine compounds (DT 297 327). In a number of known processes, the polymerization is also carried out using small amounts of polymers incompatible with polystyrene (DT Application Publications 1,520,790, 1,769,374, 2,101,666, 1,570,238, U.S. Patent Nos. 2,857,339, 2 857,340 and Japanese Patent Application Laid-Open No. 71/21453), in which a shorter cooling time was observed in some methods, while in others the additions had virtually no effect on the cooling time. Incompatible polymers include polyethylene, atactic polypropylene, polyisobutylene, polyvinylidene chloride, mixed polymers of ethylene and vinyl acetate or styrene, acrylonitrile-styrene-ethenylate and ethylenecarboxylate, N-vinylcarbazole, and condensation products of phthalic acid. . However, the high molecular weight compounds known from the prior art are not sufficiently satisfactory because they either form only slightly fluffable particles or do not allow satisfactory welding together or do not achieve shorter cooling times at all.

It has now been found that expandable styrene polymers which contain a uniformly distributed high molecular weight compound reacted therein are suitable for the preparation of particularly rapidly removable cell shaped bodies when at least 50% by weight, preferably 100% by weight of butene, is incorporated as a high molecular weight compound forming a discontinuous phase. -1-polymer or butene-1 copolymer, which for the most part, preferably 70% by weight, consists of butene-1 in amounts of 0.01-2.0% by weight. In particular, said butene-1-polymers 3,57768 are used in an amount of 0.2 to 1% by weight.

When copolymers are used which consist predominantly of butene-1, the proportion of butene-1 in the copolymer is greater than 50%, preferably at least 70% by weight, in particular from 80 to 99% by weight.

Suitable copolymers are copolymers in which the comonomers are propylene, ethylene, pentane-1, hexene-1, higher α-olefins, butadiene, or styrene, or terpolymers in which the comonomers are ethylene and propylene. an example is butene-propylene copolymers with a propylene content of 5 resp. 20% with an RSV value of 0.25, butene-ethylene copolymers with an ethylene content of 0.5 and an RSV value of 0.5, butene-hexene copolymers with a hexene content of 2.5% and an RSV value of 0.5, butene-1 ethylene-propylene terpolymers with 5% propylene and 1% ethylene "and an RSV value of 0,7. The RSV value (measured in decalin at 135 ° C) should generally be less than 3 for both homopolymers and copolymers, in particular less than 1.5.

Both partially atactic and isotactic homopolymers are suitable as homopolymers of butene-1, however, partially atactic homopolymers are particularly suitable.

In particular, according to a particular embodiment, homopolymers of butene-1 can be used in combination with other high molecular weight compounds which form a discontinuous phase. In such a case, the proportion of butene-1 should not be less than 50% of the total amount of macromolecular compounds used. As the high molecular weight compounds to be used, mention may be made in particular of ethylene vinyl acetate copolymers.

It has been found that when various macromolecular compounds are used, the polybutene (1) content can be up to 50%, when using corresponding copolymers and the butene (1) content, on the other hand, is preferably of the order of 70%, in particular> 80%.

Expandable foamable styrene polymers are in particular homopolymers of styrene or also copolymers.

Suitable comonomers are: styrene halogenated in the α-methylstyrene core, such as 2,4-dichlorostyrene, acrylonitrile, methacrylonitrile, esters of α, β-unsaturated carboxylic acids with alcohols containing 1 to 8 carbon atoms, such as acrylic acid and methacrylic acid and methacrylic acid . Comonomers are used in up to 50% by weight of styrene polymers.

57768

Propellant foamable styrene polymers contain conventional gaseous or liquid organic compounds that do not dissolve the styrene polymer, swell easily, and have a boiling point below the softening point of the polymer. Such compounds include, for example, aliphatic hydrocarbons such as propane, butane, pentane, hexane; cycloaliphatic hydrocarbons such as cyclohexane; in addition halogenated hydrocarbons such as dichlorodifluoromethane, or 1,2,2-trifluoro-1,1,2-trichloroethane. Mixtures of these compounds can also be used.

It is also possible to optionally use solvents such as methanol or ethanol with hydrocarbons and / or halogenated hydrocarbons used as propellants.

The propellants used are in amounts of 3 to 15% by weight, in particular 5 to 7% by weight, based on the polymer.

Expandable styrenic polymers are obtained in particular by suspension polymerization of monomeric styrene and optionally comonomers, using customary activators such as peroxides or azo activators and optionally with other macromolecular compounds that form a discontinuous phase. However, it is also possible to prepare fluffable styrenic polymers, for example, using a bulk polymerization process. In addition, it is possible to impregnate propellant-free styrene polymers which already contain said high molecular weight compounds and which have been obtained by known mass-resp. according to suspension methods in the form of granules or beads, with said propellants optionally in aqueous suspension or after melting in an extruder, in which case the strip-like product obtained from the extruder is comminuted while avoiding foaming.

In order to make the butene polymer as evenly distributed as possible, the polymerization is carried out in a known manner while vigorously agitating it. The particle size of the butene polymer in the styrene polymer after such treatment is ^ 20. When the particle size is smaller, the cooling time is shorter than for larger particle sizes, however, it is also not shorter in the case of very large 5,57768 particles than the cooling times that occur when using known additives. It has also been found that when equal amounts of butene polymer are used, cooling times are shorter when the molecular weight of the styrene polymer is lower. Such a reduction in molecular weight, expressed as K, can be achieved by the use of co-regulating agents in the polymerization, for example dimeric α-methylstyrene or tert-dodecyl mercaptan. These adjusting agents are used in amounts of 0.05 to 0.5% by weight, in particular 0.1 to 0.3% by weight, based on the mixture of monomers and butene polymer. The expanded styrene polymers may further contain flame retardants, plasticizers, stabilizers, antistatic agents, colorants or fillers.

Example 1:

To a pressure-resistant boiler equipped with an impeller stirrer are added 11,600 parts by weight of water and a solution of 13,700 parts by weight of styrene, 34.5 parts by weight of benzoyl peroxide, 15 parts by weight of butyl perbenzoate and 70 parts by weight of X, addition of high molecular weight substances. The polymer is first polymerized for about 2.5 hours at 90 ° C with stirring, then 1900 parts by weight of a 1% polyvinyl alcohol solution are added and further polymerized for about 3.5 hours at the same temperature. Finally, 1370 parts by weight of pentane are added and towards the end of the addition the temperature is raised to about 120 ° C and kept for about 4 hours while stirring at this temperature. After cooling, fluffy beads are obtained, which are washed, dried and pressed through a sieve to a grain size of 1-2 mm.

The expandable beads are pre-foamed in a flowing steam to a vibration weight of 20 g / l, stored for 24 hours at a time, after which they are steam foamed in a perforated mold measuring 30 x 30 x 15 cm. Steam is introduced 5 until a pressure of 0.9 aty is reached. This pressure is maintained for 30 seconds. The mold is opened when the pressure has dropped to 0.05 aty. Measure the time elapsed from the time the steam supply is switched off until the pressure has dropped to 0,05. Finally, cell-shaped bodies are also prepared so as not to wait until said pressure drop has taken place. In this case, different short times are tried. In this way, the cooling time at which post-expansion of the cell shape body still occurs is determined. The shortest cooling time without 6 57768 post-expansion of the cell shape body is mentioned below as the cooling time.

a-h denote comparative experiments, i-q denote exemplary cooling times according to the invention min.

a) without addition 31 b) Polyisobutylene 34 c) ethylene-propylene copolymer 31 d) polymethyl methacrylate (mol.p. · * »30,000) 29 e) polymethyl methacrylate (mol.p.'v 9,000) 35 f) condensation product terephthalic acid and isophthalic acid (70:30) and ethylene glycol and 2,2-dimethylpropanediol-1,3 (50: 50) 40 g) hard paraffin MW 730 33 h) hard paraffin MW 1600 31 i) partially atactic polybutene-1, 64% ether soluble, RSV 0.5 8 k) partially tactical polybutene-1 79% ether soluble, RSV 0.4 8 l) isotactic polybutene-1 RSV 0.82 17 m) butene-propylene copolymer (5% propylene) RSV 0.25 7 n) butene-propylene copolymer (20% propylene) RSV 0.3 12 o) butene-ethylene copolymer (4% ethylene) RSV 0.5 5 p) butene-hexene copolymer (2.5% hexene) RSV 0.5 5 q) butene-ethylene-propylene terpolymer (5% propylene, 1% ethylene) RSV 0.7 1

Example 2:

Example 1m is repeated, in which case, instead of 70 parts by weight, butene-propylene copolymer is used in 140 parts by weight, respectively. 28 parts by weight. For comparison, Example 1d is repeated using 140 parts by weight of polymethyl methacrylate (mol, ρ. ^ 130,000). The results are reported in the following table.

7 57768 28 parts by weight of butene-propylene copolymer cooling time (e.g. according to 1m) 70 n ti ti n n »t 7 mo» ”» "" "8 70" "polymethyl methacrylate 29 (mol. 130,000) 1H0" "" 34

Example 3:

Example 1i is repeated, using a) 70 parts by weight of partially atactic polybutene-1 with an ether-soluble component ~ of 60% and an RSV value of 0.5, and b) further working with 0.2% by weight of a control agent, dimer a methylstyrene. The following cooling times were measured.

Cooling time styrene phase min. K-value_ a) 70 parts by weight of partially atactic polybutene 8 63 b) + 0.1% by weight of dimeric α-methylstyrene 2 56

Example 4:

Example 3a is repeated, using confusing intensities of different intensities. Cooling times for polybutene particles of different sizes were measured.

Partly atakt. particle size of polybutene cooling time (discontinuous phase) in min._ «· 20 19 9 10 -S 3 5

Example 5:

Example 3a is repeated using instead of 70 parts by weight of a partially atactic polybutene-1 having an ether-soluble component of 60% and an RSV of 0.5, 35 parts by weight of this substance and an additional 35 parts by weight of an ethylene-vinyl acetate copolymer having about 45% vinyl acetate and having a melt index of about 2.

The measured cooling time is 3 minutes.

Claims (4)

57768 8 Expandable styrene polymers suitable for the preparation of rapidly removable cell moldings containing a water-insoluble high molecular weight compound which is soluble in monomeric styrene and which forms a discontinuous phase with at least 50% of the styrene polymers, characterized in that the styrene polymer contains butene-1-polymerate or butene-1 copolymer in which butene-1 is present in the majority, preferably at least 70% by weight, with high molecular weight compounds of 0.01-2.0% by weight, based on polystyrene . A process for the preparation of expandable styrene polymers according to claim 1, which are suitable for rapidly removing cell moldings from molds, by polymerizing styrene, optionally together with other olefinically unsaturated monomers to be polymerized in the presence of to form a discontinuous phase, characterized in that 0.01 to 2.0% by weight of a high molecular weight compound, based on styrene, is used, of which at least 50% by weight, preferably 100% by weight, is butene-1 polymer or butene 1 copolymer, most of which, preferably at least 70% by weight, is butene-1. 1. Expandable styrenic polymers, preferably having a cellular plastic form, in which case they are used in the form of a single molecular weight, in which case a monomeric styrene is formed, which is the same as the container. , that of the styrene-polyisates having a higher molecular weight of 50% by weight, of which 100% by weight of butene-1-polymerization or shampolymer of buLen-1, a variable buten-1 of the above-mentioned form, heated from 70 to %, varvid de högmolekylära föreningarna utgör mellan 0,01 ooh 2,0 vikt-% beräknat pä polystyrenen.