DE102009027658A1 - Ultralight and highly impact-resistant plate, useful e.g. as facade components, preferably claddings, comprises acrylic glass, obtainable by polymerizing composition of polymerizable (meth)acrylate system by chamber- or Rostero process - Google Patents

Abstract

Ultralight and highly impact-resistant plate comprises acrylic glass, obtainable by polymerizing a composition comprising a polymerizable (meth)acrylate system by chamber process or Rostero process. The polymerizable (meth)acrylate system comprises: (A) polymerizable components; (B) a (pre)polymer soluble or swellable in (A); (C) an initiator or several initiators, and/or a redox system comprising an accelerator and a peroxidic catalyst or initiator; (D) usual additives different from (E) and (F); (E) hollow microparticles; and (F) an agent for adjusting the structural viscosity. Ultralight and highly impact-resistant plate comprises acrylic glass, obtainable by polymerizing a composition comprising a polymerizable (meth)acrylate system by chamber process or Rostero process. The polymerizable (meth)acrylate system comprises: (A) polymerizable components comprising (in wt.%) (a) (meth)acrylate (greater than 50-100) containing (a1) methyl (meth)acrylate (0-100), (a2) (meth)acrylate having 2-4 carbon atoms (0-100), (a3) (meth)acrylate having >= 5 carbon atoms (0-50) and (a4) polyfunctional (meth)acrylates (0-50), and (b) comonomers (0 to less than 50) containing (b1) vinyl aromatics (0-35) and (b2) vinyl ester (0-35), where the components (a1)-(b2) are selected such that they together results in 100 wt.% of (A); (B) a (pre)polymer (0.05-15 parts by weight relative to 1 part by weight of (A)) soluble or swellable in (A); (C) an initiator or several initiators having coordinated half-life with each other, respectively in an amount sufficient to initiate the polymerization of the component (A), and/or a redox system comprising an accelerator and a peroxidic catalyst or initiator in an amount sufficient to cure the component (A); (D) usual additives different from (E) and (F); (E) hollow microparticles having an average particle size of 3-150 mu m and an average density of 0.01-0.5 g/cm 3>(3-70 wt.%, based on the sum of (A)-(F)); and (F) an agent for adjusting the structural viscosity, in an amount that is sufficient to keep the hollow microparticles (E) in the distributed state in the composition, during the chamber- or Rostero process, so that the uniformity of distribution of the microparticles (E) in the finished state, in the acrylic glass plate, is such that the relative density difference at two points of the plate at a distance of 1 cm is = 5%, where the maximum density difference between any two points on the plate is = 10%. An independent claim is also included for producing the plate, comprising mixing the components (A)-(F) with each other, and polymerizing the mixed components in a sealed chamber, which is a mold.

Description

The invention relates to ultra-light cast acrylic sheets, to processes for their production and to the use of the sheets.

Due to their flawless surfaces and the high transparency of the cast glass, panels made of solid acrylic glass have an increasing attention. Special applications for solid sheets of acrylic glass, for example, with dimensions of up to 2 × 3 m, with a thickness of the material from 10 to 30 mm, include, among other noise barriers. In addition, massive acrylic glass panels are increasingly used as a replacement for MDF panels in high-quality kitchen furniture fronts. Also in facade construction, massive acrylic glass panels with a high-gloss surface are used. A problem of the cast glass acrylic sheet, however, is its relatively unsatisfactory impact resistance. In case of impact, it is very easy to splinter the plate. In the case of noise barrier panels, the problem of low impact strength can be solved, for example, by pouring in nylon filaments which are capable of binding any splinters that may occur during fracture after impact. Although this avoids danger from splinters flying around, the plate is destroyed.

Another problem associated with solid cast glass panels is the relatively heavy weight of the solid panels. At a density of about 1.19 g / cm ³ , the square meter of a 20 mm thick solid sheet weighs about 20 kilograms. A solid plate for a noise protection wall (dimension about 2 m × 3 m × 30 mm) brings it to a stately 216 kg. In view of this high weight, it would be desirable to have a much lighter plate with the same stability and strength.

Although there are hollow sheets of acrylic glass with significantly lower weight than the solid cast glass plates and the hollow panels also have quite satisfactory strength values, but due to the production of the hollow panels by extrusion their surfaces are always due to the production of slightly lower quality than the surfaces of cast glass.

The prior art is the WO 98/45375 = PCT / EP98 / 01881 called.

D1 discloses backfilled sanitary articles comprising an acrylic molded article reinforced on its backside with fiberglass- and asbestos-free 1.5 to 10 mm thick polymeric material firmly bonded to the acrylic molded article without additional adhesion promoter, the reinforcing material or reinforcing material being cured a polymerizable, cold-curing, reactive (meth) acrylate system sprayed on the backside of the acrylic molded article, characterized in that it contains hollow microparticles filled as an inert gas-filled inert filler in an amount of 0.1 to 50% by weight on the total weight of the (meth) acrylate system. The use of preferably filled with calcium carbonate gas-filled, expanded hollow microspheres made of plastic as a filler in the (meth) acrylate resin system leads to an improvement in the mechanical properties of the backing layer, especially in terms of impact strength, adhesion and flexural strength, and in terms of testing DIN EN 198 (Hot water change test and ball drop test).

As a rule, the sanitary articles of the D1 are deep-drawn acrylic molded parts with a backing layer. Although the backfilling is fundamentally suitable for giving the molded part a certain mechanical stability, the molded part itself is solid and as such still quite heavy. In addition, because of the deep-drawing process, it does not have the surface quality of cast glass and the distribution of mechanical properties over the molded part itself is inhomogeneous, ie. H. not uniformly distributed over the molding. An application of such a reinforced molding in the construction sector, such as cladding, would be unthinkable.

With regard to the production of the known back-fed sanitary articles made of acrylic glass, it should be noted that the hollow microspheres can not be processed by conventional spraying systems because of their compressibility deviating from the surrounding cold-curing system. Either one must therefore apply the reinforcing layer by hand to the back of the molding or you have to develop new spray processing systems to make the back-lining layer mechanically applied. Both are associated with not inconsiderable expense.

In view of the prior art, it would be desirable to have a plate with a combination of properties not heretofore in theory or in practice. The new ultralight building board is said to have the extreme surface quality of cast glass and the low basis weight of hollow board panels made of extruded glass and at the same time have an improved toughness compared to both cast glass and extruded glass.

In addition, such a lightweight plate should be possible to produce by standard methods, so that no new production methods, such as special spray equipment, must be established.

The object of the invention is also the indication of uses for the new plate.

These tasks and other tasks, which are not literally mentioned in detail, but which can be deduced from the introductory discussion of the prior art readily or be deduced as a matter of course, by an ultra-light and highly impact-resistant plate made of acrylic glass with all the features of the claim 1.

Advantageous embodiments of the ultralight plate according to the invention are the subject of the claims back to the independent product claim.

With regard to the method, the features of the independent method claim indicate a solution of the problem underlying the invention with regard to the method aspects. Advantageous variants of the method are placed under protection in the method claims dependent on the independent method claim.

Preferred uses are the subject of the claims of the corresponding category.

• B) auf 1 Gew.-Teil A) 0,05–15 Gew.-Teile eines in A) löslichen oder quellbaren (Pre)polymers;
• C) einen Initiator oder mehrere Initiatoren mit aufeinander abgestimmter Halbwertszeit, jeweils in einer zur Initiierung der Polymerisation der Komponente A) ausreichenden Menge, und/oder ein Redoxsystem enthaltend einen Beschleuniger und einen peroxydischen Katalysator oder Initiator in einer Menge ausreichend zur Härtung der Komponente A);
• D) übliche von E) und F) verschiedene Additive;
• E) hohle Mikropartikel mit einer mittleren Partikelgröße im Bereich von 3 bis 150 μm und einer mittleren Dichte im Bereich von 0,01 bis 0,5 g/cm³, bezogen auf die Summe A)–F) in einer Menge von 3–70 Gew.-%; und
• F) Mittel zur Einstellung der Strukturviskosität in einer Menge, die ausreicht, die hohlen Mikropartikel E) während des Kammer- oder Rosteroverfahrens so in der Zusammensetzung verteilt zu halten, dass bei der Acrylglasplatte im fertigen Zustand die Gleichmäßigkeit der Verteilung der Mikropartikel E) in der Platte so ist, dass der relative Dichteunterschied an zwei Punkten der Platte im Abstand von 1 cm kleiner oder gleich 5% ist, wobei der maximale Dichteunterschied zwischen zwei beliebigen Punkten der Platte kleiner oder gleich 10% ist enthält,

gelingt es alle von den Norminstituten und den industriellen Verarbeitern bezüglich der physikalischen Eigenschaften der Platte aufgestellten Forderungen in herausragender Weise zu erfüllen und eine große Zahl weiterer zusätzlicher Vorteile zu erlangen.In particular, in that a sheet of acrylic glass is obtainable by polymerization of a composition according to the chamber process or rostero process, wherein the composition A) polymerizable constituents a) (meth) acrylate > 50-100% by weight a1) methyl (meth) acrylate 0-100% by weight a2) C ₂ -C ₄ (meth) acrylate 0-100% by weight a3) ≥ C ₅ (meth) acrylate 0-50% by weight a4) polyvalent (meth) acrylates 0-50% by weight b) comonomers 0- <50% by weight b1) vinyl aromatics 0-35% by weight b2) vinyl ester 0-35% by weight, wherein the components a1) to b2) are selected so that they together give 100 percent by weight of the polymerizable components A);

• B) to 1 part by weight of A) 0.05-15 parts by weight of a (A) soluble or swellable (A) polymer;
• C) one or more initiators having a matched half-life, each in an amount sufficient to initiate the polymerization of component A), and / or a redox system containing an accelerator and a peroxydic catalyst or initiator in an amount sufficient to cure component A) ;
• D) usual of E) and F) various additives;
• E) hollow microparticles having an average particle size in the range of 3 to 150 microns and a mean density in the range of 0.01 to 0.5 g / cm ³ , based on the sum A) -F) in an amount of 3-70 wt .-%; and
• F) means for adjusting the intrinsic viscosity in an amount sufficient to keep the hollow microparticles E) distributed in the composition during the chamber or raster process such that the uniformity of the distribution of the microparticles E) in the final state of the acrylic sheet is Plate is such that the relative density difference at two points of the plate at a distance of 1 cm is less than or equal to 5%, the maximum density difference between any two points of the plate being less than or equal to 10%,

It succeeds in meeting all the requirements imposed by the standards institutes and the industrial fabricators on the physical properties of the board in an outstanding manner and to obtain a large number of additional advantages.

These include:
The basis weight of the acrylic sheet is extremely low compared to acrylic glass.
The ultra-light plate according to the invention has a very high surface quality, just as known from classical acrylic cast glass.
The impact resistance of the ultra-light and impact-resistant acrylic cast glass top is unusually high compared to classic acrylic cast glass.
The acrylic glass cast plate according to the invention has in particular a high surface gloss.
The ultra-light, impact-resistant acrylic glass cast sheet with high surface quality is characterized by a high uniformity of the mechanical properties determined over the surface.
The acrylic glass cast plate can be produced by established methods for the production of acrylic cast glass.
The acrylic cast glass plate can be produced in existing tools (chambers) without the aid of other devices or tools.
Mechanical properties according to DIN EN 198 (Deformability, impact strength, rigidity) are met in an excellent manner and fulfilled beyond the required dimensions.
In addition, the risk of the occurrence of stress cracks is minimized by the preferably solvent-free nature of the (meth) acrylate system.

The ultralight and high impact acrylic sheet of high surface quality according to the invention is obtainable by polymerizing a particular and selected meth (acrylate system) according to per se known methods of making acrylic glass.

The shape of the acrylic cast glass plate

In the context of the invention, the shape and type of the acrylic molded part are initially not subject to any particular restriction. Cast glass parts made of acrylic glass in all geometries as well as conceivable and manufacturable formats are included. Preferred are rectangular shapes, such as sheets, plates or sheets whose thickness is less than their width or length. Particularly advantageous are plate-shaped parts or plates.

The methods for the production of acrylic cast glass, preferably in the form of plates, are familiar to the person skilled in the art.

The chamber method is one of the oldest methods for the bulk polymerization of ethylenically unsaturated monomers and is z. B. already in the patent US 2,154,639 described. Nevertheless, it is still of great technical importance and is very often used for the production of PMMA (cast glass) plates. In the chamber process is poured into a mixture of ethylenically unsaturated monomers and optionally the corresponding polymers in a proportion of usually up to 25 wt .-% polymer, together with radical initiator (s) and possibly other additives, such as. As crosslinkers and comonomers, in a flat chamber, which consists of two spaced plates, for. As silicate glass panes, and a sealing cord (PVC or polyolefins or other materials is formed, and polymerizes the reaction mixture.

The use of prepolymerized material (prepolymer) reduces the shrinkage, reduces the heat development in the further polymerization and shortens the reaction time. The polymerization is often carried out in a warming cabinet initially at low temperature, for. B. at 20 ° C to 60 ° C, and then usually at a higher temperature, for. B. at 100 ° C to 130 ° C completed. This results in a volume shrinkage of up to 20%, which is compensated by compressing the plates, so that stresses are avoided.

For this purpose, brackets are usually used, embrace the two plates and the intervening sealing cord and compress.

The classical chamber method is based on horizontal plates; In the Rostero process, the chambers are vertical / upright.

The (meth) acrylate system

Component A),

Component A) is an essential constituent of the (meth) acrylate system.

As the polymerizable monomer A), according to the invention, a single monomer is used or a mixture of monomers is used. In particular, component a) is an essential constituent. The composition of component A) is: A) polymerizable constituents a) (meth) acrylate > 50-100% by weight a1) methyl (meth) acrylate 0-100% by weight a2) C ₂ -C ₄ (meth) acrylate 0-100% by weight a3) ≥ C ₅ (meth) acrylate 0-50% by weight a4) polyvalent (meth) acrylates 0-50% by weight b) comonomers 0- <50% by weight b1) vinyl aromatics 0-35% by weight b2) vinyl ester 0-35% by weight, wherein the components a1) to b2) are selected so that together they add up to 100% by weight of the polymerisable constituents A).

An item in parenthesis is available here as well as throughout the specification for its optional utility, i. H. (Meth) acrylate stands for acrylate and / or methacrylate.

The monomer component A) contains at least more than 50% by weight of (meth) acrylate, monohydric (meth) acrylates having a C ₁ -C ₄ -ester residue being preferred. Particularly preferred is methyl (meth) acrylate. Longer chain esters, ie those having a C ₅ or longer chain ester radical are limited to 50% by weight in component A). The long-chain (meth) acrylates make the system impact resistant in the specified amount. The acrylic glass becomes more flexible in its use, but also softer, which would limit the performance properties in amounts above 50 wt .-%.

If poly (meth) acrylates are also present in component A), their amount is limited to a maximum of 50% by weight. Of particular interest to polyvalent (meth) acrylates are trimethyloylpropane tri (meth) acrylate, glycol di (meth) acrylate and bis ((meth) acryloyloxyethyl) sulfide, as well as mixtures having any of the foregoing components or mixtures of two or three more of the aforesaid components;

The proportion of C ₂ -C ₄ esters in (meth) acrylates is preferably limited to less than 50 wt .-% in component A), these esters are preferably less than 30 wt .-% and particularly advantageously less than 20 wt .-% in component A). Even more preferably, component A) is free from component a2).

Particularly preferred polymerizable constituents a) of the (meth) acrylate system include (meth) acrylates which are derived from saturated alcohols, for example methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Heptyl (meth) acrylate, 2-tert-butylheptyl (meth) acrylate, octyl (meth) acrylate, 3-iso-propylheptyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate , 5-methylundecyl (meth) acrylate, dodecyl (meth) acrylate, 2-methyldodecyl (meth) acrylate, tridecyl (meth) acrylate, 5-methyltridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, 2-methylhexadecyl (meth) acrylate, heptadecyl (meth) acrylate, 5-iso-propylheptadecyl (meth) acrylate, 4-tert-butyloctadecyl (meth) acrylate, 5-ethyloctadecyl (meth) acrylate, 3 iso-propyloctadecyl (meth) acrylate, Oct adecyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, cetyleicosyl (meth) acrylate, stearyleicosyl (meth) acrylate, docosyl (meth) acrylate and / or Eicosyltetratriacontyl (meth) acrylate; Cycloalkyl (meth) acrylates such as cyclopentyl (meth) acrylate, 2,3,4,5-tetra-t-butylcyclohexyl (meth) acrylate, cyclohexyl (meth) acrylate, bornyl (meth) acrylate;

Particularly suitable monofunctional (meth) acrylates are in particular methyl methacrylate, butyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, ethyltriglyl methacrylate, hydroxypropyl methacrylate, and mixtures of two or more of the above compounds and mixtures with other monomers comprising at least one of the aforementioned components.

The long-chain alcohol ester compounds, especially the alcohol-containing compounds containing 6 or more carbon atoms, can be obtained, for example, by reacting (meth) acrylates and / or the corresponding acids with long-chain fatty alcohols, generally a mixture of esters such as (meth ) acrylates with different long-chain alcohol residues. These fatty alcohols include Oxo Alcohol ^® 7911, Oxo Alcohol ^® 7900, Oxo Alcohol ^® 1100 ^® Alfol 610, Alfol ^® 810, Lial ^® 125 and Nafol ^® grades (Sasol Olefins & Surfactants GmbH); Alphanoi ^® 79 (ICI); Epal ^® 610 and Epal ^® 810 (Ethyl Corporation); Linevol ^® 79, Linevol ^® 911 and Neodol ^® 25E (Shell AG); Dehydad® ^® -, Hydrenol ^® - and Lorol ^® grades (Cognis); Acropol ^® 35 and Exxal ^® 10 (Exxon Chemicals GmbH); Kalcol 2465 (Kao Chemicals).

In a particularly preferred embodiment of the present invention, the (meth) acrylate system as polymerizable constituents A) in addition to the (meth) acrylates as further ethylenically unsaturated monomers one or more comonomers b), which can be copolymerized with compounds a).

The proportion of comonomers is limited to less than 50 wt .-%. Among these comanomers, vinylaromatics and / or vinyl esters of up to at most 35% by weight may be contained in component A). Higher levels of vinyl aromatic compounds are difficult to polymerize and can lead to a segregation of the system. Higher levels of vinyl esters can continue to harden insufficiently at low temperatures under unfavorable conditions of polymerization and tend to a larger shrinkage behavior.

Preferably, component A) to> 80-100 wt .-% and particularly preferably to> 90-100 wt .-%, expedient to> 99 wt .-%, more suitably to 100 wt .-% of (meth) acrylates constructed, as can be achieved with these monomers favorable physical processing and performance characteristics for the acrylic sheets according to the invention.

The proportion of comonomers b) in a particular embodiment is preferably in the range from 0.01 to 25.0% by weight, preferably in the range from 0.01 to 10.0% by weight, particularly preferably in the range from 0, 01 to 5.0 wt .-%, in particular in the range of 0.01 to 1.0 wt .-%, based on the total weight of the polymerizable constituents.

worin R^1* und R^2* unabhängig voneinander aus der Gruppe ausgewählt sind, aufweisend Wasserstoff, Halogene, ON, lineare oder verzweigte Alkylgruppen mit 1 bis 20, vorzugsweise 1 bis 6 und besonders bevorzugt 1 bis 4 Kohlenstoffatomen, welche mit 1 bis (2n + 1) Halogenatomen substituiert sein können, wobei n die Zahl der Kohlenstoffatome der Alkylgruppe ist (beispielsweise CF₃), Cycloalkylgruppen mit 3 bis 8 Kohlenstoffatomen, welche mit 1 bis (2n – 1) Halogenatomen, vorzugsweise Chlor, substituiert sein können, wobei n die Zahl der Kohlenstoffatome der Cycloalkylgruppe ist; Arylgruppen mit 6 bis 24 Kohlenstoffatomen, welche mit 1 bis (2n – 1) Halogenatomen, vorzugsweise Chlor, und/oder Alkylgruppen mit 1 bis 6 Kohlenstoffatomen substituiert sein können, wobei n die Zahl der Kohlenstoffatome der Arylgruppe ist; C(=Y*)R^5*, C(=Y*)NR^6*R^7*, Y*C(=Y*)R^5*, SOR^5*, SO₂R^5*, OSO₂R^5*, NR^8*SO₂R^5*, PR^5* ₂, P(=Y*)R^5* ₂, Y*PR^5* ₂, Y*P(=Y*)R^5* ₂, NR^{8 *} ₂ welche mit einer zusätzlichen R^8*-, Aryl- oder Heterocyclyl-Gruppe quaternärisiert sein kann, wobei Y* NR^{8 *}, S oder O, vorzugsweise O sein kann; R^5* eine Alkylgruppe mit 1 bis 20 Kohlenstoffatomen, eine Alkylthio mit 1 bis 20 Kohlenstoffatomen, OR¹⁵ (R¹⁵ ist Wasserstoff oder ein Alkalimetall), Alkoxy von 1 bis 20 Kohlenstoffatomen, Aryloxy oder Heterocyklyloxy ist; R^6* und R^7* unabhängig Wasserstoff oder eine Alkylgruppe mit 1 bis 20 Kohlenstoffatomen sind, und R^8* Wasserstoff, lineare oder verzweigte Alkyl- oder Arylgruppen mit 1 bis 20 Kohlenstoffatomen sind;
R^3* und R^4* unabhängig ausgewählt aus der Gruppe bestehend aus Wasserstoff, Halogen (vorzugsweise Fluor oder Chlor), Alkylgruppen mit 1 bis 6 Kohlenstoffatomen und COOR^9*, worin R^9* Wasserstoff, ein Alkalimetall oder eine Alkylgruppe mit 1 bis 40 Kohlenstoffatomen ist, sind, oder R^3* und R^4* können zusammen eine Gruppe der Formel (CH₂)_n bilden, welche mit 1 bis 2n' Halogenatomen oder C₁ bis 04 Alkylgruppen substituiert sein kann, oder der Formel C(=O)-Y*-C(=O) bilden, wobei n' von 2 bis 6, vorzugsweise 3 oder 4 ist und Y* wie zuvor definiert ist; und wobei zumindest 2 der Reste R^1*, R^2*, R^3* und R^4* Wasserstoff oder Halogen sind.Here comonomers are particularly suitable, which correspond to the following formula:

wherein R ^{1 *} and R ^{2 * are} independently selected from the group consisting of hydrogen, halogens, ON, linear or branched alkyl groups having 1 to 20, preferably 1 to 6 and particularly preferably 1 to 4 carbon atoms, which are substituted with 1 to (2n + 1) halogen atoms may be substituted, where n is the number of carbon atoms of the alkyl group (for example CF ₃ ), cycloalkyl groups having 3 to 8 carbon atoms, which may be substituted by 1 to (2n-1) halogen atoms, preferably chlorine, where n the number of carbon atoms of the cycloalkyl group is; Aryl groups of 6 to 24 carbon atoms which may be substituted with 1 to (2n-1) halogen atoms, preferably chlorine, and / or alkyl groups of 1 to 6 carbon atoms, n being the number of carbon atoms of the aryl group; C (= Y *) R ^{5 *} , C (= Y *) NR ^{6 *} R ^{7 *} , Y * C (= Y *) R ^{5 *} , SOR ^{5 *} , SO ₂ R ^{5 *} , OSO ₂ R ^{5 *} , NR ^{8 *} SO ₂ R ^{5 *} , PR ^{5 *} ₂ , P (= Y *) R ^{5 *} ₂ , Y * PR ^{5 *} ₂ , Y * P (= Y *) R ^{5 *} ₂ , NR ^{8 *} ₂ which may be quaternized with an additional R ^{8 *} , aryl or heterocyclyl group, where Y * NR ^{8 *} , S or O, preferably O; R ^{5 * is} an alkyl group having 1 to 20 carbon atoms, an alkylthio having 1 to 20 carbon atoms, OR ¹⁵ (R ¹⁵ is hydrogen or an alkali metal), alkoxy of 1 to 20 carbon atoms, aryloxy or Heterocycloxy is; R ^{6 *} and R ^{7 * are} independently hydrogen or an alkyl group of 1 to 20 carbon atoms, and R ^{8 * are} hydrogen, linear or branched alkyl or aryl groups of 1 to 20 carbon atoms;
R ^{3 *} and R ^{4 * are} independently selected from the group consisting of hydrogen, halogen (preferably fluoro or chloro), alkyl groups of 1 to 6 carbon atoms and COOR ^{9 *} , where R ^{9 * is} hydrogen, an alkali metal or an alkyl group of 1 to 40 Carbon atoms, or R ^{3 *} and R ^{4 *} may together form a group of formula (CH ₂ ) _n , which may be substituted with 1 to 2n 'halogen atoms or C ₁ to 04 alkyl groups, or of formula C (= O ) -Y * -C (= O) where n 'is from 2 to 6, preferably 3 or 4, and Y * is as previously defined; and wherein at least 2 of the radicals R ^{1 *} , R ^{2 *} , R ^{3 *} and R ^{4 * are} hydrogen or halogen.

Among the preferred comonomers include styrene, substituted styrenes having an alkyl substituent in the side chain, such as. Α-methylstyrene and α-ethylstyrene, substituted styrenes having an alkyl substituent on the ring such as vinyltoluene and p-methylstyrene, halogenated styrenes such as monochlorostyrenes, dichlorostyrenes, tribromostyrenes and tetrabromostyrenes; Vinyl halides such as vinyl chloride, vinyl fluoride, vinylidene chloride and vinylidene fluoride; Vinyl esters, such as vinyl acetate; 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, vinyloxazoles and hydrogenated vinyloxazoles; Vinyl and isoprenyl ethers; Maleic acid and maleic acid derivatives such as maleic anhydride, methylmaleic anhydride, maleimide, methylmaleimide; Fumaric acid and fumaric acid derivatives; Acrylic acid and methacrylic acid; Aryl (meth) acrylates, such as benzyl methacrylate or phenyl methacrylate, wherein the aryl radicals may each be unsubstituted or substituted up to four times; Methacrylates of halogenated alcohols such as 2,3-dibromopropyl methacrylate, 4-bromophenyl methacrylate, 1,3-dichloro-2-propyl methacrylate, 2-bromoethyl methacrylate, 2-iodoethyl methacrylate, chloromethyl methacrylate; Hydroxyalkyl (meth) acrylates such as 3-hydroxypropyl methacrylate, 3,4-dihydroxybutyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2,5-dimethyl-1,6-hexanediol (meth) acrylate, 1,10-decanediol (meth) acrylate ; carbonyl-containing methacrylates, such as 2-carboxyethylmethacrylate, carboxymethylmethacrylate, oxazolidinylethylmethacrylate, N- (methacryloyloxy) formamide, acetonylmethacrylate, N-methacryloylmorpholine, N-methacryloyl-2-pyrrolidinone, N- (2-methacryloyloxyethyl) -2-pyrrolidinone, N- (3 Methacryloyloxypropyl) -2-pyrrolidinone, N- (2-methacryloyloxypentadecyl) -2-pyrrolidinone; N- (3-Methacryloyloxyheptadecyl) -2-pyrrolidinone; Glycol methacrylates such as 1,2-butanediol methacrylate, 2-butoxyethyl methacrylate, 2-ethoxyethoxymethyl methacrylate, 2-ethoxyethyl methacrylate; Methacrylates of ether alcohols such as tetrahydrofurfuryl methacrylate, methoxyethoxyethyl methacrylate, 1-butoxypropyl methacrylate, cyclohexyloxymethyl methacrylate, methoxymethoxyethyl methacrylate, benzyloxymethyl methacrylate, furfuryl methacrylate, 2-butoxyethyl methacrylate, 2-ethoxyethoxymethyl methacrylate, 2-ethoxyethyl methacrylate, 1-ethoxybutyl methacrylate, methoxymethyl methacrylate, 1-ethoxyethyl methacrylate, ethoxymethyl methacrylate and ethoxylated (meth) acrylates which preferably have 1 to 20, in particular 2 to 8, ethoxy groups;
Aminoalkyl (meth) acrylates and aminoalkyl (meth) acrylatamides, such as N- (3-dimethylaminopropyl) methacrylamide, dimethylaminopropyl methacrylate, 3-diethylaminopentyl methacrylate, 3-dibutylaminohexadecyl (meth) acrylate; Nitriles of (meth) acrylic acid and other nitrogen-containing methacrylates such as N- (methacryloyloxyethyl) diisobutylketimine, N- (methacryloyloxyethyl) dihexadecylketimine, methacryloylamidoacetonitrile, 2-methacryloyloxyethylmethylcyanamide, cyanomethylmethacrylate; heterocyclic (meth) acrylates such as 2- (1-imidazolyl) ethyl (meth) acrylate, 2- (4-morpholinyl) ethyl (meth) acrylate and 1- (2-methacryloyloxyethyl) -2-pyrrolidone; Oxiranyl methacrylates such as 2,3-epoxybutyl methacrylate, 3,4-epoxybutyl methacrylate, 10,11-epoxyundecyl methacrylate, 2,3-epoxycyclohexyl methacrylate, 10,11-epoxyhexadecyl methacrylate; Glycidyl.

In a particularly preferred embodiment of the present invention, the ethylenically unsaturated compounds (= comonomers b)) contain one or more crosslinkers which can be conveniently copolymerized with the polymerizable constituents. In this case, compounds having at least two, preferably from 2 to 5, in particular 2, ethylenically unsaturated groups per molecule are particularly preferred.

For the purposes of the present invention, in particular the following compounds have proven particularly useful:
(Meth) acrylates derived from unsaturated alcohols, such as. Oleyl (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, 2,4,5-tri-t-butyl-3-vinylcyclohexyl (meth) acrylate, 3-vinylcyclohexyl (meth) acrylate; Methacrylates of unsaturated ether alcohols, such as vinyloxyethoxyethyl methacrylate, 1-methyl- (2-vinyloxy) ethyl methacrylate, allyloxymethyl methacrylate; and dienes, such as divinylbenzene.

These monomers can be used singly or as a mixture.

Suitable comonomers are, in particular, vinyltoluene, styrene, vinyl esters.

In this case, styrene is preferably limited to less than 20% by weight in A), since a higher content can lead to disruptions in the curing and, if necessary, greater odor nuisance would be expected.

Component B)

Component B) is an essential component.

To adjust the viscosity, the total rheology and the curing and polymerization properties, especially for better. Curing of the (meth) acrylate system, component A), a polymer or prepolymer B) is added. This (pre) polymer B) (spelling again stands for both alternatives, ie polymer and / or prepolymer) should be soluble or swellable in A). On a part A) 0.05 to 15 parts of the prepolymer B) are used. Parts in this context means parts by weight. Particularly suitable are poly (meth) acrylates, which can be dissolved as a solid polymer in A) or wherein a so-called syrup can be used, d. H. partially polymerized masses of corresponding monomers. Also suitable in minor amounts (about 0.05 to about 0.5 parts) are optionally also suitable polyvinyl chloride, polyvinyl acetate, polystyrene, epoxy resins, epoxy (meth) acrylates, unsaturated polyesters, polyurethanes or mixtures thereof. These polymers cause, for example, special flexibility properties, shrinkage regulation, act as a stabilizer, skin builder or leveling agent.

The (meth) acrylate system preferably contains 10-30 wt .-%, more preferably 15 wt .-% - 20 wt .-% of a high molecular weight polymer B), z. As poly (meth) acrylate, based on the sum A) + B).

In a preferred embodiment, the weight ratio of components B) and A) of the binder is in the range of 0.1: 1 to 2: 1. As a result, an optimal balance is achieved.

Weight ratios B): A) in the range from 0.2: 1 to 1: 1 are particularly expedient.

The components A) and B) can in the context of the invention in an expedient embodiment, completely recruit from the already mentioned above syrup. For example, a prepolymer is prepared having a polymer content of 30% by weight and a "residual monomer content" of about 70% by weight. When used alone as a syrup, this prepolymer then covers both the polymerizable constituents A) and, as a syrup, can contribute the polymer components to the polymerizable (meth) acrylate system.

Component C)

Component C) is an essential component of the (meth) acrylate system.

For the polymerization, it is expedient to add to the polymerizable constituents at least one free-radical initiator known per se. Among the preferred initiators include the azo initiators well known in the art, such as AIBN and 1,1-azobiscyclohexanecarbonitrile, and peroxy compounds such as methyl ethyl ketone peroxide, acetylacetone peroxide, dilauryl peroxide, tert-butyl per-2-ethylhexanoate, ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, dibenzoyl peroxide , tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, 2,5-bis (2-ethylhexanoylperoxy) -2,5-dimethylhexane, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxy-3,5,5- trimethylhexanoate, dicumyl peroxide, 1,1-bis (tert-butylperoxy) cyclohexane, 1,1-bis (tert-butylperoxy) 3,3,5-trimethylcyclohexane, cumyl hydroperoxide, tert-butyl hydroperoxide, bis (4-tert. butylcyclohexyl) peroxydicarbonate, mixtures of two or more of the abovementioned compounds with one another and mixtures of the abovementioned. Compounds with unspecified compounds that can also form radicals.

In particular, it is also possible to use mixtures of radical initiators having different half-lives, so that a more uniform polymerization of the acrylic glass over a relatively long period of time is made possible.

The initiators or compounds mentioned are used in an amount which is sufficient for the polymerization of the polymerizable constituents at room temperature or at higher temperatures cause. Frequently, these compounds are used in an amount of 0.1% by weight to 10.0% by weight, preferably of 0.5% by weight to 3.0% by weight, based on the total weight of the polymerisable constituents, used.

The polymerization / curing of the (meth) acrylate system according to the invention may under certain circumstances be effected by means of a redox system if, for example, the surface finish is not too high. In this case, the polymerization system contains a redox system comprising an accelerator and a peroxidic catalyst or initiator, these components being added in sufficient quantity for cold curing of component A). Usually, the redox system in an amount of 0.1001 to 5 wt .-%, based on the total weight of the polymerizable components from the sum of the weights of the components a1) to b2), is used.

It is understood that either the redox system or at least portions thereof are to be kept separate from the polymerizable substances of the system until the desired time of the polymerization.

The accelerator is usually used in an amount of 0.01 wt .-% to 2.5 wt .-% in a1) to b2), more preferably from 0.5 wt .-% to 1.5 wt .-%.

Particularly suitable accelerators are amines and mercaptans, preference is given to dimethyl-p-toluidine, diisopropoxy-p-toluidine, diethylol-p-toluidine, dimethylaniline and glycol dimercaptoacetate. Furthermore, organic metal salts which are usually used in the range from 0.001% by weight to 1% by weight in a1) to b2) serve as accelerators. Suitable z. Cobalt naphthenate, copper naphthenate, cobalt oleate, copper oleate.

Particularly suitable peroxydic catalysts are dibenzoyl peroxide and dilauroyl peroxide. The peroxides are usually used at 0.1 wt .-% to 5 wt .-% and in particular to 0.5 wt .-% to 2.5 wt .-% in the system. Suitably, the peroxydic catalyst used for the system is an aqueous 40% suspension of phlegmatized dibenzoyl peroxide (for example Cadox 40 E from Akzo).

In the system of the component C) already the accelerator, z. As dimethylparatoluidine, be included, without polymerization takes place at ambient temperature. By adding the remaining constituents of component C), the reaction is started, the component C) usually being dimensioned so that the (meth) acrylate system still has a certain pot life, which makes it possible to fill the chamber.

Component D)

Component D) is an optional component.

The (meth) acrylate system (A) to F)) may contain conventional additives D), as they can be used in acrylic glass.

The amount of these customary additives may be from 0% by weight to 50% by weight, preferably from 0% by weight to 30% by weight and more preferably from 0% by weight to 20% by weight, in each case to the sum of the weights of components A) to D).

These additives are used for. As the abolition of oxygen inhibition, this particular paraffins to 0.05 wt .-% to 5 wt .-% and / or phosphites to 0.01 wt .-% to 1 wt .-% are suitable. In addition, defoamers, wetting agents, inhibitors, matting agents, bluing agents, UV stabilizers, polymerization chain regulators and the like may be added.

As optional constituents, the (meth) acrylate system may also have one or more fillers which are preferably inert under the conditions of depolymerization of the (meth) acrylates.

If the transparency of the cast glass has no relevance, it may have various non-transparent, mostly particulate, fillers. Preference is given to fine fillers, ie those having a fineness ≦ 100 microns, and based on the weight of the (meth) acrylate system in an amount of 0 wt .-% - 75 wt .-%.

In this context, with reference to the invention, fillers which are inert under the conditions of depolymerization of the (meth) acrylates are substances which do not significantly adversely affect or even prevent the depolymerization of acrylate polymers.

Acrylate polymers, especially PMMA, are among the few plastics that are outstandingly suitable for direct chemical recycling. This is to be understood that these polymers can be completely decomposed at certain temperatures and pressures back into the corresponding monomer units (depolymerization), if heat is supplied in a suitable manner. For example, for the depolymerization of polymethyl methacrylate (PMMA) and recovery of the resulting monomeric methyl methacrylate (MMA) by thermal treatment of. Acrylic glass waste at temperatures> 200 ° C, condensation of the resulting monomer vapors and workup of the crude monomers in the literature and in the patents various continuous and discontinuous procedures described. In the most commonly used industrial process, the polymer material is placed in a partially lead-filled vessel that is heated from the outside. At temperatures above 400 ° C, the polymer material depolymerizes and the resulting monomer vapors pass through a conduit into a condenser where they are condensed to a crude, liquid monomer. Corresponding Depolymerisationsverfahren are for example from DE-OS 21 32 716 known.

As fillers mostly mineral fillers are used. In the context of the invention, fillers which can advantageously be used in the (meth) acrylate system include mica, aluminum hydroxide, calcite fillers such as chalk and marble, quartzitic fillers such as wollastonite, cristobalite and similar, amorphous silicates, fly ash, silicon carbide and / or barite ,

Of these, mica, aluminum trihydrate (aluminum hydroxide), quartzitic and calcitic fillers are particularly suitable for the invention.

The additives D) are used either alone or in combination of several. The amount is generally between 0 and 75 wt .-% based on the sum of the components A) to F) of the (meth) acrylate system.

Smooth fillers are preferred for the invention. These are to be understood as having as smooth a surface as possible particles. The particle size of the fillers according to the invention is ≦ 100 μm. They are therefore very fine fillers. The particle size of the fillers is determined by sieve analysis and is preferred in the specified size in order to ensure the processing of the (meth) acrylate system. In addition, small filler particles with a smooth surface are better enveloped by polymerizable constituents, less prone to aggregation and form no air cushion in the cast glass.

Hollow microparticles (component E)

Component E) is an essential component of the (meth) acrylate system.

Acrylic glass sheets of the invention comprise certain microparticles. These are particles with a mean size in the range from 1 to 1000 μm. Suitably 1 to 500 microns. Preferably 10 to 250 microns. Especially advantageous are average particle diameters of 50 to 200 .mu.m. In the context of the invention, the mean particle diameter should in each case be the so-called d50 value. The d50 value indicates that 50 percent of the particles are larger or smaller than the specified value. It is therefore not an average value in the classical sense. For example, the d50 value is determined by a sieve analysis.

The particles E) which can be used according to the invention are hollow particles which may be regular or irregular but which are preferably spherical or spherical and have in their cavity an inert liquid or inert gas. Inert means in this context any substance that does not chemically interact with the surrounding matrix of the acrylic glass. The inert liquid may be, for example, certain hydrocarbons, such as butane or the like, which expand under the action of temperature. The inert gas may be nitrogen or the like. Under certain conditions, air is also possible as content. The person skilled in various variants are familiar.

In the case of spherical or spherical hollow microspheres (preferably hollow spheres), the mean particle diameter of reinforcing particles useful according to the invention is in the range from 1 to 1000 μm. Preferably, the average outer diameter of the hollow microspheres is 1 to 500 microns. Particular embodiments include hollow spherical microparticles with average particle diameters between 10 and 250 microns. Extremely suitable are average particle diameters in the range of 50 to 200 microns.

The hollow spherical microparticles have a relatively low density compared to acrylic glass. This makes it possible to specifically influence the density of the sheets of acrylic and to achieve ultra-light, yet extremely stable plates.

In an expedient embodiment, the plate of the invention is characterized in that the density of the plate is in the range of 0.35 to 0.8 cm ³ / g. This corresponds to only about half the density of a conventional acrylic glass cast plate. Even more preferably, the panels of the invention have a density in the range of 0.4 to 0.7 g / cm ³ .

By a suitable selection and consideration of the particle size of the microparticles, the amount of microparticles and the density of the microparticles, it is possible to combine extremely favorable mechanical properties of the cast glass plate with a very low weight of the plates. In a preferred embodiment, the invention is characterized in that the microparticles E) have an average particle size in the range of 5 to 100 microns, have an average density in the range of 0.05 to 0.4 g / cm ³ and based on the sum the weight of the components A) -F) in an amount of 5-40 wt .-% in the (meth) acrylate system. Even more preferred are those plates in which the microparticles E) have an average particle size in the range of 8 to 80 microns, have a mean density in the range of 0.1 to 0.3 g / cm ³ and based on the sum of the weight the constituents A) -F) are present in an amount of 6-25% by weight.

The hollow microspheres which can be used particularly preferably as component E) in principle include hollow microspheres made of different materials, such as, for example, polypropylene. As glass, metals, metal oxides, polymers and organic compounds. Also preferred are mineral hollow body and ceramic hollow body.

Even more preferably, hollow plastic microspheres are used for the invention. The microparticles E) are particularly expediently gas-filled, expanded hollow microspheres made of plastic.

Particularly preferred in the present invention as component E) hollow microspheres are used which consist of polymers, such as. Polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylate, polyacrylonitrile, polybutadiene, polyethylene terephthalate; furthermore preferred are hollow microspheres of copolymers or terpolymers which are based on those monomers which form the said copolymers.

Examples of such polymers and copolymers which form the hollow spheres themselves include vinylidene chloride-acrylonitrile copolymer, polyvinylidene chloride, acrylonitrile-vinylidene chloride copolymer, acrylonitrile-methacrylonitrile copolymer, acrylonitrile-divinylbenzene-vinylidene chloride copolymer and the like.

In the context of the invention, it is also possible to use mixtures of hollow microspheres as component E).

The hollow microspheres or microparticles which can be used according to the invention may be coated with coatings to adapt the processing properties or to vary the reinforcing properties.

Also suitable are modifications of the simple hollow microspheres. For example, such hollow microspheres are of particular interest, which consist of polymers which are coated with mineral substances (coated), in order to ensure better stability against the influence of the surrounding medium (methacrylate resin).

The coating of the hollow microspheres can be made of fine-grained minerals such. For example, calcium carbonate, quartz, mica, aluminum hydroxide, cristobalite and the like.

Particularly preferred are hollow microspheres, in particular those made of plastic, which are coated with calcium carbonate.

The hollow microspheres which are particularly favorable in the context of the invention as component E) can, in principle, be prepared in the following ways and manners, among other methods:
Coating of a core (sacrificial core) with the relevant material, then the core is removed by different methods (eg dissolving in a solvent, evaporation or volatilization), so that only the shell remains. Micko hollow spheres made of ceramic materials and metal oxides are mainly produced with this method.
Production in a nozzle reactor (Nozzle-Reactor System):
In this case, the gas contained in the hollow microspheres and the liquefied material for the shell of the spheres are sprayed via specially designed nozzle systems (concentric openings).
In a kind of spray tower, the liquefied material cools and solidifies into a hollow microsphere filled with the respective gas (eg H ₂ O, CO ₂ , SO ₂ , air, N ₂ , etc.). This method is mainly used to produce hollow microspheres of polymeric materials.
Phase separation of emulsions by liquid extraction:
Here, the spherical, liquid-filled particles (micelles) present in an emulsion are separated from the surrounding liquid and then dried. This method mainly produces hollow microspheres of metal oxides, but also of polymers.

An overview of the production of hollow microspheres can be found, for example, in Mat. Res. Soc. Symp. Proc. Vol 372, 1995 Materials Research Society by David L. Wilcox, Sr. and Morris Berg, pages 3 to 13, and the literature cited therein.

Particularly suitable types of gas filled hollow microspheres of plastic include, among others, ^® Dualite types, e.g. B. ^® Dualite M 6017AE, (Pierce & Stevens Corp.); ^® Expancel types, eg B. ^® Expancel 642 WU, ^® Ropaque types, eg. B. ^® Ropaque OP 62 (Rohm and Haas Co.), Matsumoto Microsphere such. Microsphere F-30E (Matsumoto Yushi Seiyaku Co. Ltd.) and the like.

Also particularly suitable are hollow micro-particles of silicate glass such as various Q-Cel ^® grades from Osthoff Petrasch GmbH & Co. KG. It is particularly appropriate Type Q-Cel ^® 7014th

Agent for adjusting the intrinsic viscosity (component F)

The (meth) acrylate system of the invention has means for adjusting the intrinsic viscosity in an amount sufficient to keep the hollow microparticles E) distributed throughout the composition during the chamber or roster process so that the uniformity of the finished acrylic glass sheet Distribution of the microparticles E) in the plate such that the relative density difference at two points of the plate is less than or equal to 5% at a distance of 1 cm, the maximum density difference between any two points of the plate being less than or equal to 10%.

The use of the means for controlling the intrinsic viscosity prevents "flooding" of the hollow microparticles during polymerization / curing of the system. Due to the specific density differences between matrix (essentially the polymerizable components of the system) and hollow microspheres and due to the sometimes quite long polymerization process would inevitably without countermeasures to an unequal distribution of the hollow microspheres in the finished cast glass. This, in turn, would result in unwanted inhomogeneity in the mechanical properties of the plate, which would ultimately be intolerable. Therefore, the use of means for adjusting the intrinsic viscosity is indicated.

In question, therefore, all agents which do not adversely affect the polymerization and at the same time be able to ensure the uniform distribution of the particles in the surrounding matrix of polymerizable and non-polymerizable constituents. Of these, thixotropic agents are particularly preferred. These serve to improve the storage stability and the settling behavior of particles in the resin components.

The amount of the viscosity-adjusting agent depends on the amount of suspended micro-hollow particles. In a preferred variant, the means for adjusting the intrinsic viscosity F) in an amount in the range of 0.05-2.5 wt .-%, preferably 0.2-1.5 wt .-%, based on the sum of the weight the components A) -F) present.

Furthermore, it is advantageous if the plate according to the invention has the means for adjusting the intrinsic viscosity F) in a ratio (w / w) to the microparticles E) in the range of 1: 100 to 1: 1. It is of particular interest if the (meth) acrylate system, based on the fillers E), contains up to 0.5 part of thixotropic agent per part of the particles E). In the context of the invention, all thixotropic agents which are familiar to the person skilled in the art can be used, provided that no disadvantageous effects emanate from them. Usual thixotropic agents are for. For example, silica, z. As Aerosil ^® 200, Aerosil ^® 300. Also Aerosil ^® 972,180,320 expedient come in Question. Further agents which can be used with success for influencing the intrinsic viscosity include, among others, montmorillonite, sheet silicates, activators such as n-vinylpyrolidone, triethanolamine, bentonites, castor oil derivatives, mixed mineral thixotropes (MMT) and the like.

In a very expedient embodiment, the plate of the invention is characterized in that it has fumed silica having an average particle size in the range of 1 to 100 nm as the means for adjusting the intrinsic viscosity F). Here again, it is even more preferable if the plate has ^Aerosil® 200 as an agent for adjusting the intrinsic ^viscosity F).

In a preferred embodiment, the plate of the invention is characterized in that the relative density difference is less than or equal to 4%. Relative density difference means the percentage indication of the difference between two density measurements at a distance of 1 cm and indeed at any plate points. It must therefore have the two measuring points only a distance of 1 cm. The density is determined in this connection by conventional methods and familiar to the skilled worker given in g / cm ^3.

In a further preferred embodiment, a plate according to the invention is characterized in that the maximum density difference is less than or equal to 7.5%. Also, the maximum density difference is a relative density difference between two points of the plate, but it is any point without a fixed predetermined distance. The measuring point with the highest measured density as well as the point with the smallest measured density are preferred.

Particularly useful plates of the invention have a relative density difference of less than or equal to 3%.

Particularly useful are now such plates with a maximum density difference of less than or equal to 5%.

Even more preferred are plates having a relative density difference of less than or equal to 1% and a maximum density difference of less than or equal to 2%.

In an expedient embodiment, the (meth) acrylate system of the invention has means for adjusting the intrinsic viscosity so that in the final state of the acrylic sheet the uniformity of the distribution of the microparticles E) in the plate is measured as the number of particles E) in any volume element of 0.001 cm ³ not more than 30% of the arithmetic mean of the specific number of particles determined from 100 different volume elements of the plate, each of the size of 0.001 cm ³ , deviates.

• – die Komponenten A) bis F) innig miteinander vermischt; und
• – die miteinander vermischten Komponenten in einer abgedichteten Kammer als Form polymerisiert.

The present invention also includes a process for producing a plate, as described hereinbefore, in which:

• - The components A) to F) intimately mixed together; and
• - The mixed components polymerized in a sealed chamber as a mold.

In a preferred process modification, the components A) to F) are mixed outside the mold into a viscous, flowable composition and the flowable mixture is poured into a mold which already comprises at least two plates which are spaced apart by a sealing element, so that one chamber is formed, wherein the polymerization of the mixture is carried out within the chamber in a temperature range of 20 ° C to 190 ° C.

This so-called chamber method is expediently carried out in a recumbent chamber (polymerization in the manner of the classical chamber method). Alternatively, it may also be preferred to polymerize in a vertically oriented chamber (so-called roster process).

Due to their unique combination of properties, the plate according to the invention has a wide range of applications. Preferred fields of application include the use of the ultralight plate as a facade component, in particular as a panel in the field of vision, as a furniture front, especially in the kitchen area, or as Geräuschschutzwandsegement and the like. Particularly noteworthy is due to the favorable static values of the plate (high toughness at very low weight) and the application as a universally applicable facade element.

Preferred applications are especially as a furniture body in the wet area such. B. in bathrooms and swimming pools.

When using the ultralight panel according to the invention as a furniture body for bathroom furniture, not only the low weight was an advantage, but also the ease of processing and assembly.

Due to the high moisture resistance compared to conventional particle board which sources with prolonged use, the ultralight plate of the invention shows significant advantages. Due to the composition and the production no swelling can take place, therefore no loss of strength of the mechanical properties occurs.

example 1

Production of an ultralight plate (thickness about 18 mm) according to the chamber method (air polymerization)

1st approach

• 88510 g MMA syrup (MMA prepolymer with an MMA content of about 78.5% by weight and a solids content (PMMA) of about 21.5% by weight)
• 8000 g Dualite ^® 6032 (gas-filled (isobutane) coated with calcium carbonate, hollow microspheres made of acrylonitrile - copolymer having an average particle size of about 95 microns from Pierce & Stevens Corporation)
• 1000 g of Aerosil ^® 200 (thixotropic agent)
• 30 g of Manoxol (bis (2-ethylhexyl) sulfosuccinate sodium salt))
• 1500 g white paste WP 43429 (white pigment based on TiO2)
• 300 g of DMS (dimeric alpha-methystyrene = molecular weight regulator)
• 100 g TEDMA (tetraethylene glycol dimethacrylate = branching agent)
• 100 g of AVN (2,2'-azobis (2,4-dimethyl) valeronitrile = initiator)
• 10 g TINUVIN ^® P (= UV stabilizer)

2. Polymerization

From the components mentioned under 1. a flowable mixture was prepared by mixing, which was evacuated for about 30 minutes to remove residual air.

The evacuated flowable mixture was filled into a chamber consisting of 2 polished silicate glass panes and a circumferential PVC sealing cord. The filled chamber was polymerized by the air polymerization process in a heatable oven. The polymerization was started by raising the temperature to about 45.degree. It was then polymerized at about 45 ° C for 15 h. To complete the polymerization, the temperature in the oven was increased after 15 h to about 110 ° C and postpolymerized / baked for 1 h.

It was an ultra-light cast glass plate with a density of 0.65 g / cm ³ , which was readily used in the body of sanitary furniture in the bathroom and wet areas.

Example 2

Production of an ultralight plate (thickness about 12 mm) according to the chamber method (water bath method)

1st approach

• 91000 g MMA syrup (MMA prepolymer with an MMA content of about 78.5% by weight and a solids content (PMMA) of about 21.5% by weight)
• 8000 g Dualite ^® 6032 (gas-filled (isobutane) coated calcium carbonate, hollow microspheres made of acrylonitrile - copolymer having an average particle size of about 95 microns from Pierce & Stevens Corporation)
• 1000 g of Aerosil ^® 200 (thixotropic agent)
• 40 g of Manoxol (bis (2-ethylhexyl) sulfosuccinate sodium salt))
• 2000 g white paste WP 43429 (white pigment based on TiO2)
• 300 g of DMS (dimeric alpha-methylstyrene = molecular weight regulator)
• 100 g TEDMA (tetraethylene glycol dimethacrylate = branching agent)
• 100 g of AVN (2,2'-azobis (2,4-dimethyl) valeronitrile = initiator)
• 10 g TINUVIN ^® P (= UV stabilizer)

2. Polymerization

From the components mentioned under 1. a flowable mixture was prepared by mixing, which was evacuated for about 30 minutes to remove residual air.

The evacuated flowable mixture was filled into a chamber consisting of 2 polished silicate glass panes and a circumferential PVC sealing cord. The filled chamber was polymerized in a water bath by the water bath polymerization method. The polymerization was started by raising the temperature to about 45.degree. It was then polymerized at about 45 ° C for 30 h.

It was an ultra-light cast glass plate with a density of about 0.60 g / cm ³ , which was readily used in the body of sanitary furniture in the bathroom and wet areas.

3. Density determination; Determination of the density distribution.

The plate prepared by the lying water bath method was sampled at four arbitrary points on the upper side (the side which was in the water bath at the top) and at four points of the lower side (the side which was in the water bath below), and the density of these samples was determined ,
Density above: 0.5927; 0.5918; 0.5910; 0.5930 (each in g / cm ³ )
Average of four measurements: 0.59 g / cm ³
Density below: 0.5909; 0.5910; 0.5898; 0.5921 (each in g / cm ³ )
Average of four measurements: 0.59 g / cm ³

It can be seen that the densities at the top and bottom of the plate (12mm) are the same within the accuracy of the measurements. A floating / Aufschwämmen the light hollow particles could therefore be completely prevented.

Example 3

Production of an ultralight plate (15 mm by the water bath method) and determination of the density distribution.

1st approach

• 91000 g MMA syrup (MMA prepolymer with an MMA content of about 78.5% by weight and a solids content (PMMA) of about 21.5% by weight)
• 8000 g Dualite ^® 6032 (gas-filled (isobutane) coated with calcium carbonate, hollow microspheres made of acrylonitrile - copolymer having an average particle size of about 95 microns from Pierce & Stevens Corporation)
• 1000 g Aerosil ^® 200. (thixotropic agent)
• 40 g of Manoxol (bis (2-ethylhexyl) sulfosuccinate sodium salt))
• 2000 g white paste WP 43429 (white pigment based on TiO2)
• 300 g of DMS (dimeric alpha-methylstyrene = molecular weight regulator)
• 100 g TEDMA (tetraethylene glycol dimethacrylate = branching agent)
• 100 g of AVN (2,2'-azobis (2,4-dimethyl) valeronitrile = initiator)
• 10 g TINUVIN ^® P (= UV stabilizer)

2. Polymerization

The flowable mixture described under 1. was evacuated for about 60 minutes and filled in a chamber consisting of 2 silicate glass panes and comprising a circumferential PVC sealing cord. The chamber was in a water bath. The polymerization took place by the Wasserbadverfahren. It was started by raising the temperature to 45 ° C. The temperature was maintained at 45 ° C for about 20 h and then at 60 ° C for a further 1 h. After completion of the polymerization, the cast glass plate was removed from the mold. This gave a plane, high gloss ultralight plate measuring 1.22 m × 2 m × 0.015 m.

3. Determination of the density distribution

• A) Bestimmung der Dichte einer Platte (Abmessung 1220 mm × 2000 mm × 15 mm) an 3 Messpunkten in vertikaler Plattenrichtung. (Höhe h der Platte = 1220 mm). Die Probe V1 wurde in einer Höhe von 50 mm (bezogen auf den unteren Rand der Platte) entnommen. Die Probe V2 wurde in einer Höhe von 600 mm (bezogen auf den unteren Rand der Platte) entnommen. Die Probe V3 wurde in einer Höhe von 1210 mm (bezogen auf den unteren Rand der Platte) entnommen. An den entnommenen Proben wurde dann die Dichte bestimmt. Die Ergebnisse der Dichtebestimmung sind in der Tabelle 1 angegeben. Man erkennt, dass die Dichte in vertikaler Richtung im Rahmen der Messgenauigkeit konstant ist.
• B) Bestimmung der Dichteverteilung in Richtung der Plattendicke (Abmessung 1220 mm × 200 mm × 15 mm) an 6 Messpunkten längs der Dicke der Platte (Dicke der Platte d = 15 mm). Es wurden insgesamt 6 Proben der 15 mm dicken Ultraleichtplatte entnommen. Probe D1 wurde direkt an einer Plattenoberfläche entnommen; Probe D2 3 mm unterhalb der Plattenoberfläche von D1; Probe D3 6 mm unterhalb der Plattenoberfläche von D1; Probe D4 9 mm unterhalb der Plattenoberfläche von D1; Probe D5 12 mm unterhalb der Plattenoberfläche von D1; Probe D6 wurde an der Plattenunterseite entnommen.

To determine the uniformity of the distribution of the hollow microspheres in the ultra-light acrylic sheet, the density of the sheet was determined at various locations. Since the density of the acrylic glass matrix is to be assumed to be constant within the scope of the measurement accuracies, the plate density at various measuring points within the plate is decisively determined by the hollow microspheres embedded in the matrix. When a plate is made lying down (chamber method), density variances are tolerated, based on the smallest measured density of up to 7% per cm thickness of the plate.

• A) Determination of the density of a plate (dimension 1220 mm × 2000 mm × 15 mm) at 3 measuring points in the vertical plate direction. (Height h of the plate = 1220 mm). Sample V1 was taken at a height of 50 mm (relative to the lower edge of the plate). Sample V2 was taken at a height of 600 mm (relative to the lower edge of the plate). The sample V3 was taken at a height of 1210 mm (relative to the lower edge of the plate). The density was then determined on the samples taken. The results of the density determination are shown in Table 1. It can be seen that the density in the vertical direction is constant within the scope of the measurement accuracy.
• B) Determination of the density distribution in the direction of the plate thickness (dimension 1220 mm × 200 mm × 15 mm) at 6 measuring points along the thickness of the plate (thickness of the plate d = 15 mm). A total of 6 samples of the 15 mm thick ultralight plate were taken. Sample D1 was taken directly from a plate surface; Sample D2 3 mm below the plate surface of D1; Sample D3 6 mm below the plate surface of D1; Sample D4 9 mm below the plate surface of D1; Sample D5 12 mm below the plate surface of D1; Sample D6 was taken from the underside of the plate.

The results of the density distribution measurements are shown in Table 1. It can be seen that the density slightly decreases towards the plate surface. Based on 1 cm thickness, the deviation is approx. 0.75-0.72 / 0.72x100 = 4% , Relative to any points, the maximum density difference (relative) is included 0.79-0.72 / 0.72x100 = 9.7% , Table 1 thickness 0 mm 3 mm 6 mm 9 mm 12 mm 15 mm D1 0.72 D2 0.72 D3 0.74 D4 0.75 D5 0.75 D6 0.79 Vertical 50 mm 600 mm 1210 mm V1 0.74 V2 0.75 V3 0.75 The results of the density measurements in [g / cm ³ ] are given

Example 4

Production of an ultralight plate (thickness approx. 15 mm) according to the waterbath method (horizontal plate)

1st approach

• 86340 g MMA syrup (MMA prepolymer having an MMA content of about 78.5% by weight and a solids content (PMMA) of about 21.5% by weight)
• 8000 g of Q-Cel ^® 7014 (hollow microspheres of silicate glass having a particle size in the range of 10 to 200 microns of the company-Osthoff Petrasch GmbH & Co. KG)
• 1000 g of Aerosil ^® 200 (thixotropic agent)
• 50 g of manxol solution (bis (2-ethylhexyl) sulfosuccinate sodium salt)) 10% by weight in M MA
• 10 g Catafor CA 100 (quaternary ammonium compound)
• 100 g TEDMA (tetraethylene glycol dimethacrylate = branching agent)
• 10 g TINUVIN ^® P (= UV stabilizer)
• 200 g TINUVIN ^® 770 (= UV stabilizer HALS)
• 45 g of terpinene solution 50% by weight as a molecular weight regulator
• 7 g V69 (peroxide initiator)
• 27 g V82 (peroxide initiator)

2. Polymerization

From the components mentioned under 1. a flowable mixture was prepared by mixing, which was evacuated for about 30 minutes to remove residual air.

The evacuated flowable mixture was filled into a chamber consisting of 2 polished silicate glass panes and a circumferential PVC sealing cord. The filled chamber was polymerized by the water bath method. The batch was polymerized horizontally. The polymerization was started by raising the temperature to about 45.degree. It was then polymerized at about 45 ° C for 15 h. To complete the polymerization, the temperature in the oven after 15 h to about 60 ° C was increased and postpolymerized / baked for 1 h.

An ultra-light 15 mm thick cast glass plate having a density of 0.643 g / cm ^{3 was} obtained, which easily satisfied the uniformity criteria in terms of density distribution.

3. Determination of the density distribution

The density distribution was determined by the thickness of the plate. The samples were taken every 5 mm beginning with the surface of the plate (top surface in the chamber).

The density measurements gave the following values: Above 0.525 g / cm ³ 5 mm depth 0.54 g / cm ³ 10 mm depth 0.545 g / cm ³ Below 0.56 g / cm ³

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 98/45375 [0005]
• EP 98/01881 [0005]
• US 2154639 [0021]
• DE 2132716 [0068]

Cited non-patent literature

• DIN EN 198 [0006]
• DIN EN 198 [0017]

Claims (23)

Ultra-light and high-impact acrylic sheet obtainable by polymerization by the chamber process or roto-process of a composition comprising a polymerizable (meth) acrylate system comprising: A) polymerizable constituents a) (meth) acrylate > 50-100% by weight a1) methyl (meth) acrylate 0-100% by weight a2) C ₂ -C ₄ (meth) acrylate 0-100% by weight a3) ≥ C ₅ (meth) acrylate 0-50% by weight a4) polyvalent (meth) acrylates 0-50% by weight b) comonomers 0- <50% by weight b1) vinyl aromatics 0-35% by weight b2) vinyl ester 0-35% by weight, wherein the components a1) to b2) are selected so that they together give 100 percent by weight of the polymerizable components A); B) to 1 part by weight of A) 0.05-15 parts by weight of a (A) soluble or swellable (A) polymer; C) one or more initiators having a matched half-life, each in an amount sufficient to initiate the polymerization of component A), and / or a redox system containing an accelerator and a peroxydic catalyst or initiator in an amount sufficient to cure component A) ; D) usual of E) and F) various additives; E) hollow microparticles having an average particle size in the range of 3 to 150 microns and an average density in the range of 0.01 to 0.5 g / cm ³ , based on the sum A) -F) in an amount of 3-70 wt .-%; and F) means for adjusting the intrinsic viscosity in an amount sufficient to keep the hollow microparticles E) distributed in the composition during the chamber or roster process such that in the final state of the acrylic sheet the uniformity of the distribution of the microparticles E) in the plate is such that the relative density difference at two points of the plate at a distance of 1 cm is less than or equal to 5%, wherein the maximum density difference between any two points of the plate is less than or equal to 10% Plate according to claim 1, characterized in that the relative density difference is less than or equal to 4%. Plate according to claim 1 or 2, characterized in that the maximum density difference is less than or equal to 7.5%. Plate according to one of the preceding claims, characterized in that the relative density difference is less than or equal to 3%. Plate according to one of the preceding claims, characterized in that the maximum density difference is less than or equal to 5%. Plate according to one of the preceding claims, characterized in that the relative density difference is less than or equal to 1% and the maximum density difference is less than or equal to 2%. Plate according to one of the preceding claims, characterized in that the density of the plate is in the range of 0.35 to 0.8 cm ³ / g. Plate according to one of the preceding claims, characterized in that the density of the plate is in the range of 0.4 to 0.7 g / cm ³ . Plate according to one of the preceding claims, characterized in that the microparticles E) have an average particle size in the range of 5 to 100 microns, have an average density in the range of 0.05 to 0.4 g / cm ³ and based on the sum the weight of the components A) -F) in an amount of 5-40 wt .-% present. Panel according to one of the preceding claims, characterized in that the microparticles have E) has an average particle size in the range of 8 to 80 microns, have an average density in the range of 0.1 to 0.3 g / cm ^3, and based on the sum the weight of the components A) -F) in an amount of 6-25 wt .-% present. Plate according to one of the preceding claims, characterized in that the microparticles E) comprise gas-filled, expanded hollow microspheres of plastic. Plate according to claim 11, characterized in that the hollow microspheres are coated with calcium carbonate. Plate according to one of the preceding claims 1 to 8, characterized in that the microparticles E) are selected from the group consisting of ^® Dualite types, ^® Expancel types, ^® Ropaque types, Matsumoto Microsphere types and combinations of two or more of the above types. Plate according to one or more of the preceding claims, characterized in that the means for adjusting the intrinsic viscosity F) in an amount in the range of 0.05-2.5 wt .-%, preferably 0.2-1.5 wt. %, based on the sum of the weight of the components A) -F), are present. Plate according to one or more of the preceding claims, characterized in that the plate has the means for adjusting the intrinsic viscosity F) in a ratio (w / w) to the microparticles E) in the range of 1: 100 to 1: 1. Plate according to one or more of the preceding claims, characterized in that the plate has as a means for adjusting the intrinsic viscosity F) fumed silica having an average particle size in the range of 1 to 100 nm. Plate according to one or more of the preceding claims, characterized in that the plate has as a means for adjusting the ^intrinsic viscosity F) ^® Aerosil 200. Plate according to one or more of the preceding claims, characterized in that the (meth) acrylate system comprises components B): A) in a weight ratio in the range from 0.1: 1 to 2: 1. Method for producing a plate according to one of the preceding claims, characterized that he - The components A) to F) intimately mixed together; and - The mixed components polymerized in a sealed chamber as a mold. Process according to Claim 19, characterized in that the components A) to F) are mixed outside the mold to form a viscous, flowable composition and the flowable mixture is poured into a mold which already comprises at least two plates which are spaced apart by a sealing element so that a chamber is formed, wherein the polymerization of the mixture within the chamber in a temperature range of 20 ° C to 190 ° C is performed. A method according to claim 20, characterized in that polymerized in a recumbent chamber (chamber method) by the Wasserbadverfahren or the Luftpolymerisationsverfahren. A method according to claim 20, characterized in that one polymerizes in a vertically upright chamber (Rosteroprozess). Use of a plate according to claims 1 to 18 or a plate obtainable by the method according to claims 19 to 22 as a facade component, in particular as a covering in the field of vision, as a furniture front, in particular in the kitchen area, as a furniture body, in particular in the wet area of bathrooms and swimming pools, or as Lärmschutzwandsegement.