EP2566914A1

EP2566914A1 - Polymethacrylimide foam materials having reduced flammability and method for producing same

Info

Publication number: EP2566914A1
Application number: EP11706249A
Authority: EP
Inventors: Werner Geyer; Kay Bernhard; Mathias Hempler; Thomas Barthel
Original assignee: Evonik Roehm GmbH
Current assignee: Evonik Roehm GmbH
Priority date: 2010-05-06
Filing date: 2011-03-03
Publication date: 2013-03-13
Also published as: DE102010028695A1; RU2012152234A; KR20130084226A; ZA201208301B; SG184531A1; JP2013525580A; US20130041056A1; TW201213419A; WO2011138060A1

Abstract

The invention relates to compositions for producing poly(meth)acrylamide foam materials having particularly reduced flammability. The present invention further relates to a method for the production, the processing and the use thereof.

Description

Polymethacrylimide foams with reduced

Flammability and method of making this

Field of the invention

The invention relates to compositions for the preparation of polymethacrylimide foams with particular

reduced flammability. Moreover, the present invention relates to the process for their preparation, processing and use.

Polymethacrylimide foams (PMI foams) have been known for a long time. Under the trademark ROHACELL ^® , these foams find many applications, especially in the area of coating materials. To this

For example, applications include processing

Laminates, composites, foam composites,

Sandwich constructions or sandwich materials.

Coating materials are shaped bodies which consist of an outer covering layer and an inner layer

Core material are constructed. The cover layers used are materials that can absorb uniaxial or multiaxial extremely high tensile forces. Examples are glass and glass

Carbon fiber fabric or aluminum plates with

Adhesive resins are fixed on the core material. The core materials used are preferably materials with low densities, typically in the range of 30 kg / m ³ and 200 kg / m ³ . Special significance of such materials in lightweight construction, especially in aircraft or vehicle construction. In addition, the flame retardance of the materials is also of great importance in these fields of application. State of the art

The prior art polymer foams on

Polymethacrylimide (PMI) with Dimethylmethanphosphonaten (DMMP), in particular in a concentration of about 10% by weight, stabilized. See EP 0 146 892, in which DMMP and functionalized DMMP are disclosed as flame retardants for polymethacrylimide. Meanwhile, however, DMMP has been identified as a mutagen, so there is a great need for DMMP as a

Flame retardant, especially for PMI foams to replace.

However, it is well known to those skilled in the art that

in particular polymethacrylimide foams represent sensitive systems and are difficult to optimize in terms of the foaming behavior. Thus, a number of commercially available flame retardant stabilizers in such foam formulations reduce or prevent the foamability.

The list of commercial flame retardants for other applications is very long. In addition to halogen-containing

Flame retardants, some of which contain antimony oxides, can also be used phosphorus-containing compounds. Phosphorus compounds are preferred because of lower smoke toxicity in case of fire. To the

Phosphorus compounds include phosphines,

Phosphine oxides, phosphonium compounds, phosphonates,

Phosphites and / or phosphates. These compounds may be organic and / or inorganic in nature. To date, however, no flame retardant is described in the prior art, with respect to comparable

Flame retardancy and mechanical properties similar good properties of PMI foam allows.

For other polymer foams, however, are diverse

Flame retardant described. Thus, methacrylic acrylonitrile foams can be stabilized according to CN 101 544 720 with chlorinated flame retardants. However, chlorinated systems are not preferred for various reasons, especially in connection with flame retardancy or for reasons of health protection.

In EP 1 501 891 phosphorus compounds are generally described for the flameproofing of polyurethane foams. In EP 2 152 834 Alkyldimethylphosphonate to

Flame retardant improvement of epoxy resins, polyesters or polyurethanes listed. The use of

Dimehtylpropylphosphonat (DMPP) in particular for

Polyurethane foams are found in DE 44 183 07 and in CN 101 487 299. (Meth) acrylimides are described in any of these writings as matrix material.

Object Task Against the background of the technology was to develop a new flame retardant for polymethacrylimides (PMI) or

Polyacrylimide (PAI), especially for PMI or PAI foams, which is not mutagenic or carcinogenic and compared to the prior art to no negative

Influence on the foamability leads. In addition, the object was to provide a flame-retardant PMI foams, the at least the same flame retardancy, comparable

has mechanical properties as the prior art.

In addition, the object was that the foams have at least the same good thermomechanical properties and a similar good processability as the known PMI foams.

In addition, the novel PMI foams should be just as easy to produce as the PMI foams according to the prior art.

Other tasks not explicitly mentioned arise from the overall context of the following description, claims and examples.

solution

The tasks were solved by using

Dimethylpropylphosphonate (DMPP) as a flame retardant for poly (meth) acrylimide foams. Surprisingly, it was found that DMPP was the only commercially available one

Flame retardant is suitable, DMMP in

To replace poly (meth) acrylimide foams. Equally surprisingly, it has been found that DMPP must be used in concentrations higher than DMMP. The notation poly (meth) acrylimide is in the following also for polymethacrylimide (PMI) and polyacrylimide (PAI).

In particular, the objects were achieved by novel foamed poly (meth) acrylamides, which were prepared from the following mixture:

(A) 30-70% by weight, preferably 40-60% by weight

Methacrylic acid or acrylic acid,

30-60% by weight, preferably 30-50% by weight

Methacrylonitrile or acrylonitrile,

0 to 30% by weight, preferably 0 to 10% by weight, of further vinylically unsaturated monomers,

(B) 8 to 18% by weight, preferably 10 to 15% by weight

Dirnethylpropylphosphonat,

(C) 0.01-10% by weight, preferably 0.1-5% by weight of blowing agent,

(D) 0-10% by weight, preferably 0.1-5% by weight of crosslinker,

(E) 0.01-2% by weight, preferably 0.1-1% by weight

polymerization

(F) 0-10% by weight, preferably 0-5% by weight usual

additives

The poly (meth) acrylimide foam is usually obtained by foaming and crosslinking this mixture.

In particular, the poly (meth) acrylimide foam is polymerized in bulk to a plate which

optionally annealed. The foaming will

subsequently at temperatures of 150 to 250 ° C

carried out . Examples of the other vinylically unsaturated monomers mentioned under (A) are: esters of acrylic or

Methacrylic acid with lower alcohols having 1-4 C atoms, styrene, maleic acid or its anhydride, itaconic acid or its anhydride, vinylpyrrolidone, vinyl chloride and / or

Vinylidene chloride. The proportion of comonomers which can not or only with great difficulty be cyclized to anhydride or imide should not exceed 30% by weight, preferably 20% by weight and more preferably 10% by weight, based on the weight of the monomers.

As blowing agent (C), the following compounds or

Mixtures thereof are used: formamide, formic acid, urea, itaconic acid, citric acid, dicyandiamide,

Water, monoalkylureas, dimethylurea, 5,5 ^λ -Αζο-bis-5-ethyl-l, 3-dioxane, 2, 2 ^λ -Azo-bis-isobutyric acid butylamide, 2, 2 ^λ -Azo-bis-isobutyric acid-N -diethylamid, 2.2 ^λ, ^λ 4,4,4, 4 ^λ -hexamethyl 2, 2 '-azopentan, 2, 2 ^λ azo-bis-2-methyl-propane, dimethyl carbonate, di-tert-butycarbonat, Acetone cyanohydrate carbonate, methyl isobutyrate, N-methyl urethane, N-ethyl urethane, N-tert-butyl urethane, urethane, oxalic acid, maleic acid, oxyisobutyric acid, malonic acid, cyanoformamide, dimethyl maleic acid, tetraacetate of methanetetracarboxylate,

N-butyl oxamide, trimethyl methane tricarboxylate, triethyl methane tricarboxylate, and monohydric alcohols of 3-8 carbon atoms such as propanol-1, propanol-2, butanol-1, butanol-2, tert-butanol and iso-butanol. For easy crosslinking, which stabilizes the foam during the foaming process and thus enables the production of homogeneous foams, crosslinking agents (D) are used.

added. At the same time, the heat resistance and the creep behavior of the foam by crosslinking agents

improved. Possible crosslinkers can be divided into two groups: covalent crosslinkers (Dl), ie

copolymerizable polyunsaturated compounds. As such monomers z. B. allyl acrylate,

Allyl methacrylate, allylacrylamide, allylmethacrylamide,

Methylene bis-acrylamide or methacrylamide,

Diethylene bis (allyl carbonate), ethylene glycol diacrylate or dimethacrylate, diethylene glycol diacrylate or dimethacrylate, triethylene glycol diacrylate or

dimethacrylate, ethylene glycol diacrylate or

dimethacrylate, tripropylene glycol diacrylate or

dimethacrylate, 1,3-butanediol diacrylate or dimethacrylate, 1,4-butanediol diacrylate or dimethacrylate,

Neopentyldioldiacrylat or -dimethacrylat, hexanediol-1, 6-diacrylate or -dimethacrylat, trimethylolpropane diacrylate or dimethacrylate, trimethylolpropane triacrylate or - trimethacrylate, pentaerythritol triacrylate or - trimethacrylate, pentaerythritol tetraacrylate or - tetramethacrylate, the pentaerythritol derivatives in each case possibly also as a technical mixture of tri- and

tetrafunctional compounds, as well as triallyl cyanurate or triallyl isocyanurate. Another group which may be considered are ionic crosslinkers (D2). These are polyvalent metal cations that form ionic bridges between the acid groups of the copolymers.

Examples include the acrylates or methacrylates the alkaline earth metals or the zinc. Zn and Mg (meth) acrylates are preferred. The (meth) acrylate salts can also be prepared by dissolving, for example, ZnO or MgO in the monomer batch.

Alternatively, the foam may also be uncrosslinked.

Initiators (E) are compounds and

Initiator systems used, the radical

Can initiate polymerizations. Known

Classes of compounds are peroxides, hydroperoxides,

Peroxodisulfates, percarbonates, perketals, peroxyesters, hydrogen peroxide and azo compounds. examples for

Initiators are hydrogen peroxide, dibenzoyl peroxide, dicyclohexyl peroxodicarbonate, dilauryl peroxide,

Methyl ethyl ketone peroxide, acetyl acetone peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert-butyl peroctanoate, tert-butyl per-2-ethylhexanoate, tert-butyl perodecanoate, tert-amyl perpivalate, tert-butyl perpivalate, tert-butyl perbenzoate, lithium, sodium, potassium and ammonium peroxodisulfate, azobisisobutyronitrile, 2, 2-Azobisiso-2, 4-dimethylvaleronitrile, 2, 2-azobisisobutyro-nitrile, 2, 2 ^x-azo-bis (2-amidinopropane) dihydrochloride, 2- (carbamoylazo) isobutyronitrile and 4 , 4 ^λ - azobis (cyanovaleric acid). Likewise suitable

Redox initiators (H. Rauch-Puntigam, Th. Völker, acrylic and methacrylic compounds, Springer, Heidelberg, 1967 or Kirk-Othmer, Encyclopedia of Chemical Technology, Vol. 1, pages 286 ff, John Wiley & Sons, INew York, 1978) , It may be beneficial to use initiators and initiator systems

to combine different decay properties with respect to time and temperature. The initiators are preferred (E) in amounts of from 0.01 to 2% by weight, more preferably from 0.15 to 1.5% by weight, based on the total weight of

Monomers used.

Furthermore, conventional additives (F) can be added to the mixtures. These include, but are not limited to, antistatic agents, antioxidants, mold release agents, lubricants,

Dyes, flow improvers, fillers,

Light stabilizers, pigments, release agents,

Weathering agents and plasticizers.

Coating materials can be produced from the poly (meth) acrylimide foams produced according to the invention. Coating materials include one-sided with a solid

Material providing materials as well as

Sandwich materials in which the foam is surrounded on both sides by solid material. The solid materials may be films or plates. These can be made of metal, wood or preferably other polymers

Consist of materials. The connection can be made by gluing, melting or sewing.

Alternatively, fiber structures, usually made

Carbon fibers or glass fibers, presented with the foam in a tool, this is then soaked with resin and cured the template.

The poly (meth) acrylimide foams according to the invention or the layer materials produced therefrom have a broad field of application. They can be used in motor vehicles, rail vehicles, aircraft, watercraft, Spacecraft, machine parts, antennas, X-ray tables, speakers and pipes are used.

The examples given below are given for a better illustration of the present invention, but are not intended to limit the invention to the features disclosed herein.

Examples

The foaming image was visually evaluated. In this case, a comparison with the prior art according to

Comparative Example 1 made.

The fire tests and the evaluation of the results from the fire tests were carried out in accordance with standard FAR 25.853.

The density or density was determined according to ISO 845.

Comparative Example 1: DMMP To a mixture of 2800 g of methacrylic acid, 2110 g

Methacrylonitrile and 5.9 g of allyl methacrylate were added as blowing agents 66 g of water and 69 g of formamide. Furthermore, 2.0 g of tert. Butyl perpivalate, 1.5 g tert. Butyl per-2-ethyl hexanoate, 4.9 g tert-butyl perbenzoate, 4.9 g cumyl perneodecanoate, 35 g zinc oxide and 9.8 g release agent (Moldwiz INT 20E). As a flame retardant 491 g of DMMP were used.

This mixture was for 68 h at 39 ° C and in one of two glass plates of size 50x50 cm and 28 mm thick

Edge seal formed chamber polymerized. Subsequently, the polymer for final polymerization over 32 h at an increasing temperature of 32 ° C to 115 ° C was annealed.

The subsequent foaming in the hot air process was carried out at 201 ° C for 2 h. The resulting foam had a density of 118 kg / m ³ . Another sample was foamed for 2 hours at 219 ° C. The resulting foam had a density of 76 kg / m ³ .

The foams have a homogeneous foaming pattern and fully meet the requirements of the fire test.

Example 1: DMPP

To a mixture of 2400 g of methacrylic acid, 2400 g

Methacrylonitrile and 9.6 g of allyl methacrylate were added as blowing agent 144 g of formamide. Furthermore, the mixture 1.9 g tert. Butyl perpivalate, 1.4 g of tert-butyl per-2-ethyl-hexanoate, 4.8 g of tert. Butyl perbenzoate, 4.8 g Cumylperneodecanoat, 33.5 g of zinc oxide and 9, 6 g

Release agent (Moldwiz INT 20E) added. When

Flame retardants were used 600 g of DMPP.

This mixture was for 72 h at 40 ° C and in one of two glass plates of size 50x50 cm and 28 mm thick

Edge seal formed chamber polymerized.

Subsequently, the polymer for final polymerization over 32 h at an increasing temperature of 32 ° C to 115 ° C was annealed.

The subsequent foaming in the hot air process was 2h at 203 ° C. The resulting foam had a

Density of 108 kg / m ³ on. Another sample was for 2h foamed at 219 ° C. The resulting foam had a density of 70 kg / m ³ .

The foams of Example 1 have a homogeneous

Foam image on, which is not recognizable from the

Foaming can be distinguished from Comparative Example 1. Both foams fully met the requirements of the fire test.

Comparative Example 2: Vinylphosphonic acid

To a mixture of 280 g of methacrylic acid, 211 g

Methacrylonitrile and 590 mg of allyl methacrylate were added as blowing agents 6, 6 g of water and 6, 9 g of formamide. Furthermore, the mixture was 200 mg tert. Butyl perpivalate, 150 mg tert. Butyl per-2-ethyl hexanoate, 49 mg tert-butyl perbenzoate, 49 mg cumyl perneodecanoate, 3.5 g zinc oxide and 980 mg release agent (Moldwiz INT 20E). The flame retardant was 42.7 g of vinylphosphonic acid

used.

This mixture was 44 h at 50 ° C in glass ampoules

polymerized. Subsequently, the polymer was used for final polymerization for 32 h at an ascending

Temperature of 32 ° C to 115 ° C annealed. The polymer was inhomogeneous.

The subsequent foaming in the hot air process was 2h at 220 ° C. The resulting foam had a

Density of 141 kg / m ³ on. Another sample was foamed for 2 hours at 230 ° C. The resulting foam had a density of 102 kg / m ³ . Both samples foamed unevenly and failed in the burn test. Comparative Example 3: Vinylphosphonic acid dimethylester

Quantities and procedure analogous to Comparative Example 2. As a flame retardant were 53.8 g

Vinylphosphonic acid dimethylester used.

This mixture was 20 h at 50 ° C in glass ampoules

polymerized. Subsequently, the polymer was to

Final polymerization for 32 h at an ascending

Temperature of 32 ° C to 115 ° C annealed. The polymer was inhomogeneous.

The subsequent foaming in the hot air process was 2 hours at 200 ° C. The resulting foam had a

Density of 80 kg / m ³ . Another sample was foamed for 2 h at 210 ° C. The resulting foam had a density of 58 kg / m ³ . Both samples foamed unevenly and failed in the burn test.

Comparative Example 4: Exolit OP 550 (Clariant)

Quantities and procedure analogous to Comparative Example 2. As a flame retardant 72.2 g of Exolit OP 550 were used. This mixture was polymerized for 41.5 h at 50 ° C in glass ampoules. Subsequently, the solid but cloudy polymer for final polymerization over 32 h at an increasing temperature of 32 ° C to 115 ° C was annealed.

The subsequent foaming in the hot air process was unsuccessful. The samples did not foam.

Comparative Example 5: Exolit OP 560 (Clariant)

Quantities and procedure analogous to Comparative Example 2. 102.1 g of Exolit OP 560 were used as the flame retardant. This mixture was polymerized for 41.5 h at 50 ° C in glass ampoules. Subsequently, the cloudy and partially still liquid polymer for final polymerization over 32 h at an increasing temperature of 32 ° C to 115 ° C was annealed.

The selection of flame retardants from Comparative Examples 2 to 5 listed here shows that none of the conventionally used flame retardants is suitable for producing a stable, refractory and at the same time homogeneous foam. Only the DMPP used according to the invention leads to a result comparable to the prior art. And this is preferred only when used in a higher concentration than DMMP.

Claims

claims

1. poly (meth) acrylimide foam, characterized

characterized in that the foam

Dimethylpropylphosphonat contains.

2. poly (meth) acrylimide foam according to claim 1, characterized in that the foamed

Poly (meth) acrylamide from a mixture consisting of

(A) 30 to 70% by weight of methacrylic acid or acrylic acid,

From 30 to 60% by weight of methacrylonitrile or acrylonitrile, from 0 to 30% by weight of further vinylically unsaturated monomers, (B) from 8 to 18% by weight of dimethyl propyl phosphonate,

(C) 0.01 to 10% by weight of blowing agent,

(D) 0 to 10% by weight of crosslinker,

(E) 0.01 to 2% by weight of polymerization initiators

(F) 0 to 10% by weight of conventional additives was prepared.

3. poly (meth) acrylimide foam according to claim 2, characterized in that the mixture consists of

(A) 40 to 60% by weight of methacrylic acid or acrylic acid, 30 to 50% by weight of methacrylonitrile or acrylonitrile,

0 to 10% by weight of further vinylically unsaturated monomers,

(B) 10 to 15% by weight of dimethylpropyl phosphonate,

(C) 0.1 to 5% by weight of blowing agent, (D) 0.1 to 5% by weight of crosslinker,

(E) 0.1 to 1% by weight of polymerization initiators and

(F) 0 to 5% by weight of conventional additives.

Poly (meth) acrylimide foam, according to at least one of claims 1 to 3, characterized in that it is obtained by foaming and crosslinking of the mixture according to claim 1 or 2.

Poly (meth) acrylimide foam, according to at least one of claims 1 to 4, characterized in that it polymerizes in substance to a plate, which is optionally tempered and then foamed at temperatures of 150 to 250 ° C.

Layer material containing a layer of a

Poly (meth) acrylimide foam according to one of claims 1 to 5.

Motor vehicle, rail vehicle, watercraft,

Aircraft, spacecraft characterized in that it partially consists of a poly (meth) acrylimide foam according to one of claims 1 to 5.

Machine part, antenna, X-ray table, loudspeaker, pipe, characterized in that it partly consists of a poly (meth) acrylimide foam according to one of claims 1 to 5.