DE10130772C1 - Acrylic resin for making flame-retardant plastics, e.g. acrylic glass, useful in aircraft, building, floor coating or lacquer, contains phosphorus compound and cyclic organo-sulfur compound - Google Patents

Abstract

Acrylic resin for flame-retardant plastics comprises: (A) 4-15 wt.% phosphorus compound(s) (I); (B) 1-4 wt.% cyclic organo-sulfur compound(s) (II); (C) 20-95 wt.% (meth)acrylate; (D) 0-75 wt.% comonomer; (E) 0-75 wt.% polymer soluble in (C) or (D), to a total of 100 wt.%; and (F) initiator. Independent claims are also included for the following: (1) Acrylic glass obtained by polymerization of this resin; (2) Use of a synergistic mixture of 4-15 wt.% (I) and 1-4 wt.% (II), for flame proofing acrylic resin, with respect to total (I), (II) and resin.

Description

The present invention relates to acrylic resins from which flame retardant plastics are available, acrylic glass, by polymerization of the resins of the invention available as well as the use of new mixtures for flame retardancy of polymers.

Poly (meth) acrylates have been known for a long time and because of their excellent mechanical and optical properties a wide application. For example, they are used in aircraft construction, construction, for coating floors and more recently also for Production of furniture used. For many of these Numerous applications require them meet fire safety requirements, which in legal requirements and a number of others Rules are laid down.

The proof that the plastics the meet fire safety requirements, is with Help a variety of different fire tests made, which usually to the respective Use of the plastic are matched. To pass These tests are generally the equipment of the Plastics with so-called flame retardants necessary.

Furthermore, the use of chlorine or bromine-containing Compounds known as flame retardants. This Compounds are common with antimony oxides used. The disadvantage here, however, that Poly (meth) acrylates, their flammability thereby is diminished, extremely poorly recyclable, since these halogenated hydrocarbons hardly from the polymer  can be separated. Extremely questionable here is that from these compounds in waste incineration plants Dioxins can arise.

In addition, in case of fire, toxic gases, such as For example, HCl and HBr, formed in the event of fire Smoke poisoning. Based on these Disadvantages, it is general purpose, chlorinated and brominated substances as additives in plastics avoid as much as possible.

Another class of flame retardants, with which poly (meth) acrylates are equipped, are Phosphorus compounds. However, these are connections not as effective as the previously described chlorine or bromine-containing substances. Accordingly, these must Compounds are used in high quantities, so that the Fire safety standards can be met.

Unfortunately, many of these act as flame retardants used phosphorus compounds as plasticizers. at Use of high amounts of these phosphorus compounds show the plastics therefore poor mechanical Characteristics. In addition, those with high quantities a phosphorus compounds equipped plastics very high water absorption, with further disadvantages accompanied.

The DT 17 94 056 C3 are flame retardant Polyacrylate-based devices known from a Acrylic acid ester polymer exist in which evenly distributed organic or inorganic Phosphorus compounds are present as flame retardants.

DE 33 11 832 A1 describes fire retardant equipped Polymethylmethacrylat molding compositions, wherein the molding composition between 8 and 15% by weight of at least one Chloralkylphophorsäureester contains.

In view of the disclosure and discussion herein Prior art, it was therefore the task of present invention, mixtures of compounds specify that are suitable synergistically To reduce the flammability of polymers. In particular the total requirement for flame retardants to be used for Compliance with fire safety standards is necessary, reduced  be, where possible to halogenated Connections should be omitted.

In addition, the flame-retardant plastic should be good show mechanical and optical properties.

Another object of the invention was to To provide poly (meth) acrylic acrylic glasses, the comparable low flammability reduced amounts to have phosphorus compounds.

Furthermore, the invention was based on the object a cost-effective flame retardancy for polymers specify.

Furthermore, the plastics should be as inexpensive as possible be recyclable without toxic compounds, especially when burning the plastics arise can.

Moreover, it was therefore the task of the present Invention that for the equipment of (meth) acrylic resins used flame retardants under health Aspects should be as harmless as possible.

Furthermore, an inventively equipped should Plastic obtained by the polymerization of acrylic resins of the present invention, one possible show little flue gas development.

These tasks are solved as well as others, although can not be called literal, but from the here discussed contexts as a matter of course derive or inevitably from these revealed by acrylic resins with all the features of the  Claim 1. Appropriate modifications of the Resin compositions according to the invention are disclosed in US Pat Claim 1 dependent claims under protection posed.

The solution of the task with regard to an acrylic glass is provided by the subject-matter of claim 7 posed. Inventive embodiments of the acrylic glass are disclosed by claims 8 to 14.

Regarding the use of synergistic mixtures the subject matter of claim 15 provides a solution of The object underlying the invention.

Due to the fact that acrylic resins

• A) 4 to 15% by weight of phosphorus compounds,
• B) 1 to 4% by weight of cyclic organosulfur compounds;
• C) 20-95% by weight of (meth) acrylates,
• D) 0-75% by weight of comonomers,
• E) 0-75% by weight of polymers soluble in (C) or (D),

where components A) to E) give 100% by weight, and

• A) have initiators,

succeeds in not easily predictable way by polymerization of acrylic resins plastics To provide that low at high flame retardance Have quantities of phosphorus compounds.

Furthermore, the acrylic resins can be used to produce acrylic glasses with an overall outstanding property spectrum:

• - Leave the resins and acrylic glasses according to the invention cost-effectively, as the amount of expensive Flame retardants by the synergistic effect  reduced the cyclic organosulfur compounds can be.
• - Plastics obtained from the resins, in particular Acrylic glasses show excellent optical and mechanical properties. In addition, the Water absorption of plastics relative to the excellent fire protection properties very low.
• Acrylic glasses of the present invention can be recycled cost-effectively, as the proportion of halogenated compounds can be reduced. In particularly preferred embodiments may halogenated compounds completely omitted become.
• - In case of fire arise from the by polymerization the resins obtained resins no or only very small amounts of toxic Halocarbons.

Component A)

In the component A) of the acrylic resin according to the invention are essentially well-known and generally commercially available phosphorus-containing Flame retardants. The phosphorus compounds include including phosphines, phosphine oxides, Phosphonium compounds, phosphonates, phosphites and / or Phosphates. These compounds may be more organic and / or inorganic nature, derivatives of these Compounds such as phosphoric acid monoester,  Phosphoric acid diester and phosphoric acid triester and Polyphosphates should be included.

Preference is given to phosphorus-containing compounds which have a unsaturated group, more preferably one Vinyl group.

Furthermore, phosphorus compounds of the formula (I) are preferred

X-CH ₂ -P (O) (OR) ₂ (I),

wherein R is the same or different radicals from the group consisting of methyl, ethyl and chloromethyl and X is a hydrogen or halogen atom, a hydroxy group or a group R ¹ O-CO-, wherein R ^{1 is} methyl, ethyl or chloromethyl.

Examples of phosphorus compounds include
Phospholene oxide, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, dimethyl phosphonate, vinyl phosphonic acid, dimethyl vinyl phosphonic acid ester, diethyl vinyl phosphonic acid diester,
2- (Dibutylphosphono) ethyl (meth) acrylate,
2- (Dimethylphosphato) propyl (meth) acrylate,
2- (Ethylenphosphito) propyl (meth) acrylate,
Dimethylphosphinomethyl (meth) acrylate,
Dimethylphosphonoethyl (meth) acrylate,
Diethyl (meth) acryloylphosphonat,
Diethylphosphatoethyl (meth) acrylate,
Dipropyl (meth) acryloyl phosphate,
Dimethylmethanephosphonate (DMMP),
Diethylmethanphosphonat,
Dimethylchlormethanphosphonat,
Diethylchlormethanphosphonat,
Dimethylhydroxymethanphosphonat,
Diethylhydroxymethanphosphonat,
Methoxycarbonylmethanphosphonsäuredimethylester and
Ethoxycarbonylmethanphosphonsäurediethylester.

The phosphorus compounds can be used singly or as a mixture be used. In this case, in particular mixtures preferably, the phosphorus compounds with unsaturated Groups, preferably vinyl groups.

These compounds are used in an amount of 4 to 15% by weight, preferably from 5 to 12.5 wt .-%, based on the weight of components A) to E), used to in synergistic effect with those set forth below cyclic organosulfur compounds Fire safety standards to meet. When using larger Quantities of these compounds can be the others thermal and mechanical properties of the Plastics, such as flexural strength and the Vicat softening temperature, worsen.

Component B)

In addition to the phosphorus compounds contain the resins of the invention 1 to 4 wt .-%, preferably 2 up to 3% by weight, based on the weight of the components A) to E), one or more cyclic Organo-sulfur compounds. The cyclic ones Sulfur compounds can be used singly or as a mixture be used to work together with the previously described phosphorus compounds the flammability of polymers.

These compounds are well known in the art and partially commercially available. It is a matter of  cyclic aliphatic or aromatic compounds which in the ring have a sulfur atom, these substances also be referred to as sulfur heterocycles.

These include substances that include a containing sulfur-containing heteroaromatic ring system. Sulfur-containing heteroaromatic ring systems are of aromatic ring systems, such as benzene, Toluene, xylene, naphthalene, 2-methylnaphthalene, Acenaphthylene, acenaphthene, fluorene, phenanthrene, Anthracene, fluoranthene, pyrene, benz [a] anthracene, chrysene, Benzo [b] fluoranthene, benzo [k] fluoranthene, benzo [a] pyrene, Dibenz [a, h] anthracene, with at least 2 replaced adjacent CH groups of the ring system by S. are. These compounds may be next to one or more Sulfur atoms also other heteroatoms, in particular Have nitrogen and / or oxygen atoms, wherein a or more sulfur atoms also to the sulfoxide or to Sulfone can be oxidized. To these connections include thiophene, thianthrene, thioxanthene, Thiopyran, isothiaxole, thiazole, phenothiazine, 1,3,4-thiadiazole, 1,2,4-thiadiazole, benzo [b] thiophene and Benzo [c] thiophene.

In addition, cyclic organosulfur compounds also substances containing a heteroaliphatic ring system contain. These are cycloalkyl radicals, in which at least one carbon unit of the Ringsystems is replaced by sulfur. This Compounds can be many times the ones mentioned above derived heteroaromatic sulfur compounds be by at least part of the double bonds be reduced. Examples include, among others Thiiranes such as thiirane, thiirane-1-oxide, Thiirane-1,1-dioxide, thiethan, thiethan-1-oxide, thiethan  1,1-dioxide, thiolane, thiolane-1-1-oxide, thiolane-1,1- dioxide, dihydrothiophene, tetrahydrothiopyran, Dihydrothiopyran, hexamethylene sulfide and Heptamethylensulfid.

In addition, also derivatives of these compounds such as Sultone and / or Sultame and Sulfates and sulfoamides of these compounds.

The size of the ring is not critical. Preferably However, the ring has a size of 3 to 12, especially preferably from 5 to 6 members, without thereby a restriction should be made.

More preferably, at least one of the organosulfur compounds is selected from the group consisting of
1,4 butane sultone:

Acesulfame H:

benzothiadiazole:

2H-benzothiazine-3 (4H) one:

2,4-thiazolidinedione:

Thiophene-2-carboxylic acid:

thianthrene:

and derivatives of these compounds.

Derivatives are, in particular, compounds derived from the previously derived. It is under to substances such as substituents respectively. These include u. a. linear, branched or cyclic alkyl radicals of up to 20 carbon atoms, the  Both saturated and unsaturated can be as for example, methyl, ethyl, propyl, butyl, pentyl, Hexyl, cyclopentyl, cyclohexyl, propenyl, butenyl, as well as linear, branched or cyclic alkoxy radicals with up to 20 carbon atoms, both saturated and may be unsaturated, such as methoxy, Ethoxy, propoxy, and butoxy. Furthermore, the Derivatives also have aryl groups, which are also heteroatoms may contain, such as phenyl, biphenylyl, Naphthyl, imidazole, indyl and the aforementioned sulfur-containing heterocycles. In addition, you can these substances also contain other functional groups, such as amino groups, epoxy groups, Keto groups, carboxy groups, ester groups and Hydroxy groups. If the compounds acid or may have basic properties, even the salts these compounds are used.

Of these substances, compounds are particularly preferred that do not contain an aromatic ring, like for example, 1,4-butane sultone, 2,4-thiazolidine quinone, Acesulfame H and thiophene-2-carboxylic acid.

In particular embodiments of the present invention cyclic organosulfur compounds are used, their decomposition temperature is at least 150 ° C, preferably at least 200 ° C, and more preferably at least 230 ° C is.

Component C)

The acrylic resin according to the invention has from 20 to 95% by weight, preferably 50 to 90 and more preferably 60 to 85% by weight, based on the weight of components A) to  E), one or more (meth) acrylates. Here are Resins which are at least 40% by weight Contain methyl methacrylate. These monomers are in the Well-known and commercially available. Of the Term "(meth) acrylate" means acrylate, methacrylate as well as mixtures of both. These connections can used singly or as a mixture.

These include (meth) acrylates derived from saturated alcohols, such as
Methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, butyl (meth) acrylate,
Pentyl (meth) acrylate, hexyl (meth) acrylate,
2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate;
(Meth) acrylates derived from unsaturated alcohols, such as. For example, oleyl (meth) acrylate,
2-propynyl (meth) acrylate, allyl (meth) acrylate,
Vinyl (meth) acrylate, etc .;
Amides and nitriles of (meth) acrylic acid, such as
N- (3-dimethylaminopropyl) (meth) acrylamide,
N- (diethylphosphono) (meth) acrylamide,
1-Methacryloylamido-2-methyl-2-propanol;
Cycloalkyl (meth) acrylates, such as
3-vinylcyclohexyl (meth) acrylate, bornyl (meth) acrylate;
Hydroxylalkyl (meth) acrylates, such as
3-hydroxypropyl (meth) acrylate,
3,4-dihydroxybutyl (meth) acrylate,
2-hydroxyethyl (meth) acrylate,
2-hydroxypropyl (meth) acrylate;
Glycol di (meth) acrylates, such as 1,4-butanediol (meth) acrylate,
(Meth) acrylates of ether alcohols, such as
Tetrahydrofurfuryl (meth) acrylate,
Vinyloxyethoxyethyl (meth) acrylate; and
polyvalent (meth) acrylates, such as
Trimethyloylpropantri (meth) acrylate.

Component D)

In addition to the (meth) acrylates set out above, the acrylic resins according to the invention also contain other unsaturated Have monomers with the aforementioned Methacrylates are copolymerizable. In general These compounds are in an amount of 0 to 75 wt .-%, preferably 0 to 20 wt .-%, based based on the weight of components A) to E), wherein the comonomers used singly or as a mixture can be.

These include, inter alia, 1-alkenes, such as hexene-1, heptene-1; branched alkenes such as vinylcyclohexane, 3,3-dimethyl-1-propene, 3-methyl-1-diisobutylene, 4-methylpentene-1;
Vinyl esters, such as vinyl acetate;
Styrene, substituted styrenes having an alkyl substituent in the side chain, such as. For example, α-methylstyrene and α-ethylstyrene, substituted styrenes with an alkyl substituent on the ring, such as vinyl toluene
and p-methylstyrene, halogenated styrenes, such as
for example, monochlorostyrenes, dichlorostyrenes, tribromostyrenes and tetrabromostyrenes;
Heterocyclic vinyl compounds, such as 2-vinylpyridine, 3-vinylpyridine, 2-methyl-5-vinylpyridine, 3-ethyl-4-vinylpyridine, 2,3-dimethyl-5-vinylpyridine, vinylpyrimidine, vinylpiperidine, 9-vinylcarbazole, 3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole, 2-methyl-1-vinylimidazole, N-vinylpyrrolidone, 2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam, N-vinylbutyrolactam, vinyloxolane, vinylfuran, vinylthiophene, vinylthiolane, vinylthiazoles and hydrogenated vinylthiazoles, vinyloxazoles and hydrogenated vinyloxazoles;
Vinyl and isoprenyl ethers;
Maleic acid derivatives, such as
Maleic anhydride, methylmaleic anhydride, maleimide, methylmaleimide; and
Dienes, such as divinylbenzene.

Component E)

For adjusting the viscosity of the reaction resin, for better curing or other properties of the resin or the polymerized polymer can the Components A) to D) one or more polymers or Prepolymers are added. This (pre) polymer should be in the components A) to D) soluble or at least swellable be, wherein the component E) is optional. She is in the general in the range of 0 to 75 wt .-%, preferably from 10 to 20 wt .-%, based on the weight of Components A) to E) used.

In particular, z. As poly (meth) acrylates as a component E), which is dissolved as a solid polymer in C) can be. They can also be called so-called Syrups, d. H. as partially polymerized masses corresponding monomers are used.

Furthermore, inter alia polyvinyl chlorides, Polyvinyl acetates, polystyrenes, epoxy resins, Epoxy (meth) acrylates, unsaturated polyesters, polyuretane or mixtures thereof or with the o. g. Poly (meth) acrylates are suitable as component E). in this connection Copolymers can also be used.  

Component F)

The polymerization of the resin of the invention can radically, being thermally, by blasting or initiated by initiators.

Depending on the intended use of the resin, the Initiator systems selected, each in the art are well known.

Among the preferred initiators include the Well-known azo initiators in the art such as AIBN and 1,1-azobiscyclohexanecarbonitrile, as well Peroxy compounds, such as methyl ethyl ketone peroxide, Acetylacetone peroxide, ketone peroxide, Methyl isobutyl ketone peroxide, cyclohexanone peroxide, Dibenzoyl peroxide, tert-butyl peroxybenzoate, tert. Butyl peroxyisopropyl carbonate, 2,5-bis (2-ethylhexanoyl peroxy) -2,5-dimethylhexane, tert-butylperoxy-2 ethylhexanoate, tert-butylperoxy-3,5,5-trimethylhexanoate, 1,1-bis (tert-butylperoxy) cyclohexane, 1,1-bis (tert. butylperoxy) 3,3,5-trimethylcyclohexane, cumyl hydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide, bis (4-tert. butylcyclohexyl) peroxydicarbonate, mixtures of two or more of the aforementioned compounds with each other as well Mixtures of the aforementioned compounds with not mentioned compounds which also form radicals can.

The initiators are usually used in an amount Range of 0.01 to 10 wt .-%, preferably from 0.5 to 5% by weight, based on the sum of the components A) to E).  

In addition, initiator systems are known which be used for cold hardening. These initiator systems are mainly used for floor coating resins as well used for resin coatings. In general, these have Initiators a redox system from an accelerator and one or more of the previously described peroxidic Catalysts or initiators. The hereby used quantities must be used for cold curing of the resin suffice.

The accelerator is usually used in an amount of 0.01 to 5% by weight, preferably 0.5 to 1.5% by weight, based on the sum of components A) to E), used. Among the most suitable as accelerators Compounds include, inter alia, amines and mercaptans, such as dimethyl-p-toluidine, diisopropoxy-p- toluidine, n, n-bis- (2-hydroxyethyl) -p-toluidine, Dimethylaniline and glycol dimercaptoacetate, where n, n-bis- (2-hydroxyethyl) -p-toluidine and dimethyl-p-toluidine completely are particularly preferred.

Furthermore, as an accelerator organic Metal salts, which are usually in the range of 0.001 to 2 wt .-%, based on the sum of the Components A) to E) are used. To this belong u. a. Copper naphthenate and copper oleate.

In addition, the inventive acrylic resin, or the available acrylic glass more widely contain known additives. These additives include including molecular weight regulators, release agents, Antistatic agents, antioxidants, mold release agents, Flame retardants, lubricants, dyes, Flow improvers, fillers, Light stabilizers, pigments, weathering agents  and plasticizer. It should be noted that halogenated flame retardants have no negative influence to the present invention. Accordingly These compounds may well be in the resins of the invention or the available therefrom Plastics be present. However, the proportion should be on halogenated compounds from those in the introduction mentioned reasons are kept as low as possible.

The additives are in the usual amount, d. H. up to 80 wt .-%, preferably up to 30 wt .-%, based on the Total mass used. Is the amount greater than 80 wt .-%, based on the total mass, so can Properties of plastics such as the Processing be disturbed.

According to a particular aspect of the present invention can acrylic resins from the acrylic resins according to the invention which are based on their Flame retardancy, excellent mechanical and have optical properties.

Thus, according to the invention, acrylic glasses can be obtained which have an E-modulus ≧ 2,800 MPa, preferably ≧ 3,000 MPa in accordance with DIN 53 457 (at 1 mm / min). Furthermore, acrylic glasses according to the invention can be produced which show an impact strength ≧ 25 mmN / mm ² , preferably ≧ 30 mmN / mm ² according to DIN 53 453. The flexural strength of the acrylic glass can be adjusted to values ≧ 100 N / mm ² according to DIN 53 452. Also, the elongation at break of the acrylic glass with values ≧ 25% according to DIN 455-1-3 (at 1 mm / min) is excellent, if desired. In addition, plastics with tensile strengths ≧ 55, preferably ≧ 60 according to DIN 53 455-1-3 (at 1 mm / min) can be produced, which have an excellent fire protection properties.

It is particularly surprising that the flame-retardant acrylic glass can have a transmittance τ _D65 ≧ 88%, preferably ≧ 90% according to DIN 5036 Part 3. The above-mentioned mechanical and / or optical properties of the acrylic glass are not intended to limit the invention. On the contrary, these details serve to illustrate the particularly excellent properties of the acrylic glass, which can be achieved with a simultaneously good fire protection property.

The acrylic can be made in a known manner. Here, the shape of the plastic body can be arbitrary be, with particular preference plastic plates getting produced.

A preferred form includes, for example, two Glass plates, a ceiling plate and a bottom plate, the sealed on the sides with appropriate measures and be separated, such. B. ribbons or Kederschnüren. The glass plates can z. B. together with metal brackets be kept and have, for example, an area of 2 m.3 m and a thickness of about 2 to 20, preferably 3 up to 12 mm. Furthermore, so-called Multiple chambers, in particular double chambers, known, the have a layered structure, wherein the middle Glass plates on both sides with the polymerizable Have mass contact.

In addition, as already mentioned, the resin can be so Be equipped for floor coatings suitable is. Furthermore, resins according to the invention also be used as paints. Depending on the type of  Use the above components in used in different quantities.

The reduced flammability of the resins obtainable by the resin can be determined, for example, by the Underwriters Laboratory UL 94 HB standard. In this case, 127 mm long and 12.7 wide specimen is provided with 2 measuring marks, wherein a part of the plastic is ignited with a flame. A classification into the class UL 94 HB is achieved, if

• a) the burning rate between 2 measuring marks 38 mm / min does not exceed, for samples with thicknesses of 3 mm and more,
• b) the burning rate between the measuring marks 76 mm / min does not exceed, for samples with thicknesses below 3 mm or
• c) the samples before reaching the 102 mm mark extinguished.

The structure of the test is well known and for example in fire behavior of plastics, Fundamentals regulations test procedure of Dr. med. Jürgen Troitzsch, published by Carl-Hanser-Verlag Munich, 1981 shown.

In addition, the reduced flammability can also through the so-called LOI values (Low Oxygen Index) be determined. The higher the LOI, the harder flammable is the tested material. The LOI values can be determined according to ASTM D 2863, for example.

The LOI value corresponds to an oxygen-nitrogen Gas mixture, one at the top lit Plastic sample, which is present as a shaped body just yet completely burned off.  

Furthermore, the good features of the Plastic in terms of fire safety standards by the SBZ test (Single Burning Item). in this connection a test arrangement is constructed in which two Plastic panels are placed over corner. In the corner a sandbox is introduced, which acts as a burner. After lighting the gas flowing through the sand studied the reaction of the plastic. This is the time to inflame the plastic, the Speed of the flame propagation as well as the heat and Smoke release of the plastic and the nature of the Burning observed.

Favorable here are great times to the ignition of the Plastic, a low propagation speed the flame on the plastic, as well as a low heat and smoke release of the plastic. This test is in "standardization and legislation in Europe" by R. Dewitt in Polymer Degradation and Stability, 64, (1999) 535-544 described.

In addition, show acrylic glasses according to the invention and Floor coatings and / or paints made of acrylic resins obtained by the present invention Flue gas development. The smoke can for example, according to ASTM-E 662. This Norm is for example in International Plastic Flammability Handbook, Hansa-Verlag, Munich 1983, Chapter 7, page 394.

By using a synergistic mixture of 4 to 15% by weight of one or more phosphorus compounds and 1 to 4 wt .-% of one or more cyclic Organosulfur compounds for flame retardancy of acrylic resins, where the weight percentages are based on the sum of  the weight of phosphorus compounds, the Relate to organosulfur compounds and acrylic resins, The proportion of flame retardant can be significant be reduced. Here, acrylic resins are preferred, the have at least 50 wt .-% acrylic polymers.

The invention will be described with reference to the appended drawings Examples explained in more detail, without thereby a Restriction is to take place. The% data refers on the total weight of the composition, unless another is noted. The flammability of the by the Resin available plastics was according to the above described UL 94 HB standard of Underwriters Laboratory certainly. The thickness of all samples was 3 mm.

example 1

It was a mix
84.235% methyl methacrylate,
0.200% di-2-ethylhexyl phosphate,
0.040% dilauryl peroxide,
0.030% tert-butyl perneodecanoate,
0.250% 2,2'-azobis (2-methylbutane),
0.040% dodecylmercaptan,
0.005% octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox 1076),
0.200% of 2- (hydroxy-5-methylphenyl) benzotriazole (®Tinuvin P),
2.500% 1,4 butane sultone (from Fluka),
5,000% triethyl phosphate and
7.500% vinylphosphonic acid produced.

This mixture was poured into a mold and placed on hardened way known. After curing for 17 hours  Resin at 45 ° C and 3 hours annealing at 100 ° C was the Plastic body taken out of shape. Subsequently was the flammability of the plastic body according to the UL 94 HB standard tested. Overall, this way 5 samples prepared and tested. The Average focal length was about 5.8 mm. About that In addition, it was surprisingly found that Plastic body with this composition also a Achieve classification V0 according to UL-94 standard.

Example 2

Example 1 was substantially repeated, with instead of 2.5% by weight of 1,4-butane sultone but 2.5% by weight Acesulfame H (from Nutrinova) were used. The from 5 Samples specific focal length was average 4.6 mm.

Example 3

Example 1 was substantially repeated, with instead of 2.5% by weight of 1,4-butane sultone but 2.5% by weight 2,4-thiazolidinedione (ex Fluka). From 5 samples of certain focal length was average 5 mm.

Example 4

Example 1 was substantially repeated, with instead of 2.5% by weight of 1,4-butane sultone but 2.5% by weight Thianthren (by Fluka) were used. The out of 5 samples certain focal length was 4.8 mm on average.  

Example 5

Example 1 was substantially repeated, with however, on the use of 5 wt .-% triethyl phosphate was omitted and 2.5 wt .-% acesulfame H (Hoechst) used instead of the specified amount of 1,4-butane sultone has been. The amount of the remaining ingredients was increased proportionally.

The average burning distance, based on 8 samples, was 18.8 mm, with the samples averaging 175.8 sec are extinguished.

Comparative Example 1

A mixture according to Example 1 was prepared, wherein however, the 1,4-butane sultone, the triethyl phosphate and the Vinylphosphonic acid by conventional halogenated Flame retardants were replaced. The halogen-containing Flame retardants were in a concentration of 12 wt .-%, based on the total mass used. The Amount of the remaining components were corresponding customized.

Five samples were made, the thickness of which was 3 mm. The average burning distance of the 5 samples was 20.4 mm, with the samples extinguished after 178 seconds are.

Claims (16)

1. Acrylic resins, from which flame-retardant plastics are available, comprising:

• A) 4 to 15% by weight of phosphorus compounds,
• B) 1 to 4% by weight of cyclic organosulfur compounds,
• C) 20-95% by weight of (meth) acrylates,
• D) 0-75% by weight of comonomers,
• E) 0-75 wt .-% in (C) or (D) soluble polymers, wherein the components A) to E) give 100 wt .-%, and
• F) Initiators.

2. acrylic resins according to claim 1, characterized that the phosphorus compounds in an amount in Range of 5 to 12.5 wt .-%, based on the Weight of components A) to E), are present. 3. acrylic resins according to claim 1 or 2, characterized characterized in that the resin is at least 40% by weight Methyl methacrylate, based on the weight of Components A) to E) contains. 4. acrylic resins according to any one of the preceding claims, characterized in that at least one of Phosphorus compounds has a vinyl group. 5. acrylic resins according to any one of the preceding claims, characterized in that the cyclic Organosulfur compounds in an amount in the range from 2 to 3 wt .-%, based on the weight of Components A) to E) are present.   6. acrylic resins according to any one of the preceding claims, characterized in that at least one of Organosulfur compounds is selected from the Group consisting of 1,4-butane sultone, acesulfame H, Benzothiadiazole, 2H-benzothiazine, 2,4-thiazolidine quinone, thiophene-2-carboxylic acid and Thianthren and derivatives of these compounds. 7. Acrylic glass obtainable by polymerization of Acrylic resins according to one or more of the claims 1 to 6. 8. Acrylic glass according to claim 7, characterized that the modulus ≧ 2800 MPa according to DIN 53 457 (1 mm / min). 9. Acrylic glass according to claim 7 or 8, characterized in that the transmittance of the acrylic glass τ _D65 ≧ 88% according to DIN 5036 Part 3. 10. Acrylic glass according to one of claims 7 to 9, characterized in that the impact strength of the acrylic glass ≧ 30 mmN / mm ² according to DIN 53 453. 11. Acrylic glass according to one of claims 7 to 10, characterized in that the flexural strength of the acrylic glass is ≧ 100 N / mm ² according to DIN 53 452. 12. Acrylic glass according to one of claims 7 to 11, characterized in that the elongation at break of the Acrylic glass ≧ 25% according to DIN 53 455-1-3 (1 mm / min) is.   13. Acrylic glass according to one of claims 7 to 12, characterized in that the tensile strength 55, according to DIN 53 455-1-3 (1 mm / min). 14. Acrylic glass according to one of claims 7 to 13, characterized in that the acrylic glass the Fire protection standard according to UL 94 HB. 15. Using a synergistic mixture of 4 to 15% by weight of one or more phosphorus compounds and 1 to 4 wt .-% of one or more cyclic Organosulfur compounds for flame retardancy of Acrylic resins, wherein the weight percentages each on the sum of the weight of Phosphorus compounds, organosulfur compounds and acrylic resins. 16. Use according to claim 15, characterized characterized in that the acrylic resins contain at least 50% by weight Acrylic polymers, based on the Weight of acrylic resins.