DE2304028C3 - Flame-resistant, expandable molding compounds made from styrene polymers - Google Patents

Description

The invention relates to flame-retardant, expandable molding compositions made from styrene polymers which contain organic bromine compounds as flame-retardant agents.

Expandable styrene polymers with the aid of halogens or halogen compounds are known to equip flame retardant. In particular, bromine or bromine compounds because of their better effectiveness used. 2-4 percent by weight of bromine is sufficient in the expandable styrene polymers, while 20 to 30 percent by weight of chlorine is required.

The bromine compounds can be added to the monomeric styrene (DBP 10 02 125) during the polymerization. or the expandable small-particle polystyrene can be added, with one for better or has used additional solvents and / or distributing agents for a more even distribution of the bromine compounds (DBPP 10 67 586, 10 90 851 and 10 90 852). Tris (dibromopropyl) phosphate has proven to be particularly useful bromine compounds for making expandable styrene polymers flame retardant. Saturated or unsaturated bromine compounds des cycloaliphatic hydrocarbon with ^ carbon atoms CDBP 1046313, DT-AS 1218149, 1128975) l These ■ "* connections lead to useful flameproof expandable styrene polymer seeds, but have the disadvantage that in the necessary amount the weldability of the pre-expanded polystyrene beads is worsened and the molded articles produced therefrom have a deteriorated cell structure.

It is known that the demouldability can be improved with very small amounts of the brominated C _{) 2} ring hydrocarbons (DT-AS 12 56 888). This is also achieved by polymerizing small amounts of bromine-containing monomers into the expandable

t5 polystyrene (DT-AS 12 82 935), however, adequate flame protection and adequate Welding of the pre-expanded polystyrene beads equipped in this way cannot be achieved with it. It is also known telomerization products from to produce jS-pinene with tetrahalocarbon and use as a flame retardant for plastics (US-PS 25 64 685). Such flame retardants are but not suitable for making expandable styrene polymers flame-retardant because the corresponding the bromine compounds have a low thermal stability and discoloration of the plastic to lead.

It is also known that copolymers of et-olefins with 2-4 carbon atoms, halogen-containing alpha-ols fines, such as vinyl chloride and, for example, tetrabromo carbon are suitable as flame retardants (DT-OS 19 If 681). However, these copolymers show in the flame-resistant finishing of expandability styrene polymers the disadvantage that because of the low Bromine content of the telomeres larger amounts of Flammscttau-iiiutel are required. This will be Cell structure and welding of the foam negatively affected

It is also known as 1,2,3,4-tetrabromobutane

To use flame retardants for styrene copolymers, but its use in expandable styrene polymers is not sufficient Flame retardancy to form parts that can be quickly deformed. The object of the invention is to provide an organic To find bromine compound which, with small amounts, is at least as good as flame-retardant Utilization, a better welding of the pre-expanded polystyrene particles is achieved and is suitable for the production of rapidly demoldable cell bodies.

jo Furthermore, the molded bodies produced should have a have fine-cell structure.

It has now been found that the desired success can be achieved if the intumescent Styrene polymers as an organic bromine compound those of the general formula

R-CHBr-CH ₂ -CBr ₂ X

in which X is a bromine or hydrogen atom and R is an aliphatic radical having 1 to 16 carbon atoms or represents an aromatic radical with 6 to 10 carbon atoms, this radical R optionally also through further halogen atoms can be substituted, contained in such amounts that the bromine content, based on the Styrene polymer, 0.1 to 5 percent by weight It is particularly advantageous to use bromine compounds in which the radical R is a aliphatic radical with 4 to 8 carbon atoms or an aromatic radical with 6 carbon atoms

represents, it being possible for these substituents R also to be substituted by halogen atoms.
Suitable bromine compounds are, for example

l.l.U-tetrabromoheptane. l. ^ - tribromoheptane,

M, l> tetrabromononane, l, 13-tribromononane,

1 ^ 1,3-tetrabromopentadecane,

' TbShl

1 _t ^ p
those in which the radical R is substituted by halogen atoms may be mentioned:

1 ^ 1,3,4-pentabromobutane,

1 ^, 1,3,4,5-hexabromopentane,

liUAS.e & e-octabromoctane,

l, l, U-tetrabromo-3- (p-bromophenyl) propane.
The bromine compounds are also advantageous in such halogenated hydrocarbons such as dichlorodifluoromethane or l ^ -trffluoro-U ^ -tri-chloroethane. Mixtures of these compounds can also be used.

If necessary, solvents such as methanol or ethanol mixed with hydrocarbons can also be used and / or halogenated hydrocarbons are used as blowing agents.

It is also possible to use so-called solid propellants as pore regulators, for example a mixture of sodium bicarbonate with organic acids such as citric acid or boric acid.

The propellants are used in amounts of 3 to 15 percent by weight, in particular from 5 to 7 percent by weight

Amounts used that the Bromgehali, based on, ₅ percent based on the polymer used,

the Styirolpolyraensat, 0.5 to 1.5 percent by weight.

is _Ä "u" i, _A ·. l., " _c ,," .. S ^en can during the polymerization, which is preferred

It also st moghch the claimed Bromverbm- _a l _s suspension polymerization in the presence of conventional

fertilize together with well-known synergistic activators such as peroxides or azo activators and

Zen. beisp.elsweise organic peroxides, such as D, tert, ₂₀ suspension stabilizers such as tricalcium phosphate or

butyl peroxide, D.cumyl peroxide Di-tert-butyl-perbenzo-organic colloids such as polyvinylpyrrolidone or

ate or organic radical formers such as phenylsubstitu- "· ated etnanes, disulfides, azo compounds and hydra-quinone dioxins, benzothiazolesulfonamides.

zinderivaie.

Furthermore, the flame-retardant effect of the _2S claimed compounds can be increased by adding phosphorus and antimony compounds. These synergists are used in amounts of 0.05 to 1.0 percent by weight, in particular 0.1 to 0.5 percent by weight, based on the styrene polymer.

When using such synergists, the bromine content in the blowing agent-containing styrene polymer 0.05 to 0.7 percent by weight, in particular 0.2 to 0.5 percent by weight. Bromine, based on the styrene polymer, at ragen.

The bromine compounds used according to the invention can be obtained by reacting carbon tetrabromide or bromoform with optionally substituted olefins (Sosnowsky, Free Radical Reactions in Prep. Org. Chemistry [1964]). _{4 <3}

Expandable styrene polymers are homo- or copolymers of styrene.

Possible comonomers are:

ft-methylstyrene, nuclear halogenated styrene such as 2,4-dichlorostyrene, acrylonitrile, methacrylonitrile, ester »^ -Unsaturated carboxylic acids with alcohols from 1 to Contains 8 carbon atoms, such as acrylic and methacrylic esters and vinyl carbazole. The comonomers are contained in the styrene polymers to a maximum of 50 percent by weight.

In addition, the expandable styrene polymers can be used in very small amounts between 0.001 and about 1 Percent by weight of polymers which contain a discontinuous with the styrene polymer during foaming Form phase, for example polyolefins such as polyethylene, polypropylene, polybutene or elastomers Polymers such as polybutadiene, rubber-like butadiene-styrene copolymers or polysiloxanes or ethylene-vinyl acetate copolymers.

The foamable styrene polymers contain the customary gaseous or liquid blowing agents organic compounds that do not dissolve or only swell the styrene polymer and their boiling points lie below the softening point of the polymers.

Such compounds are, for example, aliphatic hydrocarbons such as propane, butane, pentane, hexane, cycloaliphatic hydrocarbons such as cyclohexane hydroxyethyl cellulose and in the presence of those mentioned Propellant is carried out, are added to the monomeric styrene. Advantageously, one becomes the flame-retardant bromine compounds against the small-scale expandable styrene polymers Add at the end of or after the polymerization of the aqueous suspension.

In a particular embodiment of the method, those present in the suspension can Polymers still contain 0 to 10 percent by weight, in particular 0 to 1 percent by weight, of monomers.

In this case, the polymerization is in the presence the flame retardant bromine compounds to the end.

However, it is also possible to use the expandable kleinteili gene styrene polymers with the flame-retardant To coat bromine compounds.

The flame retardancy is determined according to the following test: A test specimen (dimensions 30 χ 30 χ 120 mm) is clamped vertically and another horizontally in a holder and up to Burning the material (3 to 4 seconds) with a non-glowing Bunsen burner flame approx. 3 cm high ignited. After removing the flame, the afterburn time is measured in seconds and used for Comparison used.

The welding of the individual particles is determined as follows:

The welding of the individual particles in the finished foam is defined as the percentage of the particles that are torn through when the foam body is broken to the total number of particles at the fracture surface.

The cooling time is measured in a form of size 30 30 χ 15 cm, the so-called Lendle machine. The cooling time is the period of time in which the pressure rises again after the steam treatment Zero drops.

example 1

11,650 parts by weight of styrofoam are polymerized in the presence of 28 parts by weight of dibenzoyl peroxide and 7 parts by weight of dicumyl peroxide, 20 parts by weight of polyvinyl alcohol and 17,045 parts by weight of water with the addition of 1165 parts by weight of pentane. After completion of the Polymerisaiionsreaktion (monomer content approximately 0.1%), the suspension to 110 ⁰ C.

brought and 200 parts by weight (1.74 percent by weight, based on polystyrene) 1,1,13-tetrabromononane added. After 4-6 hours at this temperature, the aqueous phase is cooled to room temperature separated The expandable, flasunproof polystyrene beads are dried in the usual way and to test specimens with the dimensions 30 χ 30 χ 120 mm. The test results are shown in Table 1

Example 2

The procedure is as in Example 1. Instead of 200 parts by weight of 1,1,1,3-tetrabromononane, 200 parts by weight of 1,1,1,3-tetrabromoheptane are used

Example 3

The procedure is as in Example 1. Instead, 100 parts by weight (0.86 percent by weight, based on polystyrene) 1,1,13-tetrabromononane and an additional 25 parts by weight (0.21 percent by weight, based on polystyrene) dicumyl peroxide as a synergist used.

Table 1

Flame test afterburn time

Welding Kühlzcit

min

Cell structure μπι

example 1
Example 2
Example 3

Comparative example 1
Comparative example 2

Example 4
You put in a bottle

7th

7th

8 canceled 10 8 10 10 25 18

30-80

40-100

20-80

100-160

80-120

60 g bead-shaped styrene polymer,

2.5 ml pentane,

120 g 1% polyvinyl alcohol solution,

0.6 g alkyl benzene sulphate,
03 g tricalcium phosphate and
1.2 g 1,1,13-tetrabromononane
(2 percent by weight, calculated on polystyrene).

Example 7

The procedure is as in Example 4; instead of 1,1,1,3-tetrabromononane, however, one uses
1,1,1,3-tetrabromo-3-phenyl-propanein.

The sealed bottle is at 100 to 24 hours 120 ° C shaken After cooling down and opening the From the bottle, the foamable polystyrene beads are filtered off and washed free of phosphate. Punched Metal molds (30 30 χ 100 mm) are loaded with 5 g of the obtained polystyrene beads and then treated in boiling water. The foam bodies obtained are after drying at 50 ° C in a vacuum oven according to the conditions described examined for their fire behavior and their bromine content. The results are summarized in Table 2.

Example 5

The procedure is as in Example 4; However, instead of 1.2 g, only 0.6 g of 1,1,1,3-tetrabromononane (1 Percent by weight, based on polystyrene).

55

Example 6

The procedure is as in Example 4; however, 1.2 g of 1,1,3-tribromononane are used as a flame retardant used.

Example 8

The procedure is as in Example 4; instead of 1,1,1,3-tetrabromononane, however, 1.2 g 1,1,1,3,4,5-hexabromopentane used.

Example 9

One works according to Example 4; instead of 1,1,1,3-tetrabromononane, however, 0.9 g 1,1,1,3,5,8,8,8-octabromoctane (1.5 percent by weight, based on polystyrene) are used

Comparative example 1

The procedure is as in Example 1, with 200 parts by weight instead of 1,1,1,3-tetrabromononane (1.74 percent by weight, based on polystyrene) tris (2,3-dibromopropyl) phosphate can be used.

Comparative example 2

The procedure is as in Example 1, but instead of 1,1,1,3-tetrabromononane as a flame-retardant Substance 200 parts by weight (1.74 percent by weight) of hexabromocyclododecane can be used.

Comparative example 3

One works according to Example 4; as a comparison substance instead of 1,1,13-tetrabromonan 1.2 g of I ^ .S.e & 10-hexabromocyclododecane were used.

Comparative example 4

The procedure described in Example 4 is followed and 0.9 g of hexabromocyclododecane are added as a flame retardant.

Table 2

Example no. Substance

Bromgehall Flammmtesi, Nach-

of the test burning time in lake

body

% Brisk. horizontal.

Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Comparative Example 3 Comparative example 4

1,1,1,3-tetrabromononane

1,1,1,3-tetrabromononane

U, 3-tribromononane

l, l, l, 3-tetrabromo-3-phenyl-propane

1,1,1,3,4,5-hexabromopentane

1,1,1,3,5,8,8,8-octabromactane

1,2,5,6,9,10-hexabromocyclododecane

1,2,5,6,9,10-hexabromocyclododecane 0.98

1.03 7th 6.5 0.47 15th 12th 1.01 10 11th 0.64 15th 13th 1.20 6th 5 0.62 13th 13th 1.40 8th 7th

20th

Claims (4)

Patent claims: 1. Heavily flammable, expandable molding compounds of styrene polymers which contain organic bromine compounds as flame retardants, characterized in that bromine compounds of the general formula R-CHBr-CH ₂ -CBr ₂ X in which X is a bromine or hydrogen atom and R is an aliphatic radical with 1 to 16 carbon atoms or an aromatic radical with 6 to Represents 10 carbon atoms, this radical R optionally also being replaced by further halogen atoms can be substituted, are contained in such amounts that the bromine content, based on the Styrene polymer is 0.1 to 5 percent by weight 2. A process for preparing flame-retardant blähfähiger styrene polymer as claimed in claim 1, characterized in that expandable styrene polymers in small-scale aqueous suspension at temperatures between 80 and 150 ⁰ C and bromine compounds of general formula R-CHBr-CH ₂ -CBr ₂ X in which X is a bromine or hydrogen atom and R is an aliphatic radical with 1 to 16 carbon atoms or an aromatic radical with 6 to Represents 10 carbon atoms, this radical R optionally also being replaced by further halogen atoms can be substituted, treated 3. The method according to claim 2, characterized in that a styrene polymer is used which contains 0 to 10, preferably 0 to 1 percent by weight of monomeric proportions 4. The method according to claim 3, characterized in that the monomer-containing styrene polymer in the presence of the bromine compound to the end is polymerized.