COMPOSITION COMPRISING A HEMIPEROXYACETAL, METHOD FOR POLYMERIZING SAME, USE THEREOF, AND COMPOSITION MATERIAL OBTAINED UPON POLYMERIZATION OF THE COMPOSITION

Abstract

The present invention relates to a composition comprising at least one (meth)acrylic monomer, optionally at least one (meth)acrylic copolymer and at least one organic peroxide chosen from hemiperoxyacetals. The invention also relates to the use of said at least one organic peroxide for the polymerization of a composition comprising at least one acrylic monomer and optionally at least one acrylic copolymer, to the use of the composition of the invention for the manufacture of resins, to a process for manufacturing thermoplastic, thermoset or composite parts, and also to the parts obtained themselves.

Claims

1-17. (canceled)

18. A composition comprising: a) at least one (meth)acrylic monomer, b) optionally at least one (meth)acrylic polymer, and c) at least one organic peroxide selected from the group consisting of hemiperoxyacetals, d) at least one additional peroxide selected from the group consisting of peroxyacetals, said composition having a dynamic viscosity of between 10 mPa.Math.s and 10 000 mPa.Math.s at 25° C.

19. The composition as claimed in claim 18, wherein the content of organic peroxide is between 0.1 phr and 15 phr, relative to the weight sum of the at least one (meth)acrylic monomer and of the optional at least one (meth)acrylic polymer.

20. The composition as claimed in claim 18, wherein the (meth)acrylic polymer comprises at least 50%, by weight of methyl methacrylate.

21. The composition as claimed in claim 18, wherein the peroxide is selected from the group consisting of hemiperoxyacetals having a half-life temperature at one minute and at atmospheric pressure ranging from 125° C. to 160° C.

22. The composition as claimed in claim 18, wherein the peroxide is selected from the group consisting of hemiperoxyacetals corresponding to the general formula (I) below: ##STR00003## in which formula (I): R1 represents a linear or branched C1-C4 alkyl group, R2 represents a branched C4-C12 alkyl group, n denotes zero or is an integer ranging from 1 to 3, R3 represents a linear or branched C1-C3 alkyl group.

23. The composition as claimed in claim 18, wherein the peroxide(s) are selected from the group consisting of 1-methoxy-1-tert-amylperoxycyclohexane (TAPMC), 1-methoxy-1-t-butylperoxycyclohexane (TBPMC), 1-methoxy-1-t-amylperoxy-3,3,5-trimethylcyclohexane, 1-methoxy-1-t-butylperoxy-3,3,5-trimethylcyclohexane, 1-ethoxy-1-t-amylperoxycyclohexane, 1-ethoxy-1-t-butylperoxycyclohexane, 1-ethoxy-1-t-butyl-3,3,5-peroxycyclohexane and mixtures thereof.

24. The composition as claimed in claim 18, wherein the peroxide is 1-methoxy-1-tert-amylperoxycyclohexane.

25. The composition as claimed in claim 18, wherein said at least one additional peroxide is selected from the group consisting of the peroxyacetals corresponding to the general formula (II) below: ##STR00004## in which formula (II) R.sub.4 to R.sub.11, which may be identical or different, represent a linear, branched or cyclic C1-C6 alkyl group.

26. The composition as claimed in claim 18, wherein the additional peroxide(s) are selected from the group consisting of 1,1-di(tert-amylperoxy)cyclohexane, 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane), 2,2-bis(4,4-di(tert-butylperoxy)cyclohexyl)propane and 1,1-di(tert-butylperoxy)cyclohexane and a mixture thereof.

27. The composition as claimed in claim 18, wherein the (meth)acrylic monomer is chosen from the group consisting of methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid, n-butyl acrylate, isobutyl acrylate, n-butyl methacrylate, isobutyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, hydroxyethyl acrylate and hydroxyethyl methacrylate, and mixtures thereof.

28. The composition as claimed in claim 18, comprising up to 20 phr of a mineral filler, relative to the weight sum of the (meth)acrylic monomer and of the optional (meth)acrylic polymer.

29. A process for preparing a composition as claimed in claim 18, said process comprising the following steps: i. preparation of a mixture of (meth)acrylic polymer and/or of (meth)acrylic monomer ii. addition of at least one organic peroxide chosen from hemiperoxyacetals and of one or more distinct additional organic peroxides.

30. A process for manufacturing thermoplastic, thermoset or composite parts, comprising the following steps: i) optionally, a step of preparing the composition of claim 18, ii) placing the composition in a mold, iii) polymerization of said composition.

31. The process as claimed in claim 30, wherein the polymerization step is performed at a temperature of between 50° C. and 140° C.

32. A part obtained via the process as claimed in claim 30.

Description

EXAMPLES

[0179] Preparation of the Test Compositions

1) Composition a According to the Invention Comprising 1.8 Phr of a Hemiperoxyacetal and 0.2 Phr of Peroxyacetal

[0180] A liquid composition A is prepared by dissolving 20% by weight of the PMMA (BS520, an MMA copolymer comprising ethyl acrylate as comonomer) in 80% by weight of methyl methacrylate, which is stabilized with HQME (hydroquinone monomethyl ether).

[0181] 3 g of peroxide system TAPMC+1,1-di(tert-amylperoxy)cyclohexane are added to 150 g of this liquid composition, and the whole is stirred for 1 minute.

2) Composition B According to the Invention Comprising 1.67 Phr of a Hemiperoxyacetal, 0.19 Phr of Peroxyacetal and 18.6 Phr of a Mineral Filler

[0182] 11.5 g of PMMA beads are added to 150 g of a liquid composition A as prepared according to example 1. The mixture is stirred for 40 minutes at 40° C. using a heating magnetic stirrer.

[0183] 30 g of quartz flour (mineral filler) and 3 g of peroxide system TAPMC+1,1-di(tert-amylperoxy)cyclohexane are then added to the mixture.

3) Composition C Comprising 2 Phr of an Organic Peroxide of Perester Type

[0184] 3 g of Trigonox® 141 (2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane) are added to 150 g of a liquid composition A as prepared according to example 1, and the whole is mixed for 1 minute.

4) Composition D Comprising 1.86 Phr of an Organic Peroxide of Perester Type and 18.6 Phr of a Mineral Filler

[0185] 11.5 g of PMMA beads are added to 150 g of a liquid composition A as prepared according to example 1. The mixture is stirred for 40 minutes at 40° C. using a heating magnetic stirrer.

[0186] 30 g of quartz flour (mineral filler) and 3 g of Trigonox® 141 are then added to the mixture.

[0187] Preparation of the Experimental Assembly

[0188] Molds were made by means of two glass plates of 20 cm×20 cm×3.85 mm assembled in parallel by means of a transparent PVC bead joint with a diameter of 4.80 mm, and the ends of the joint were then welded to ensure the final leaktightness of the molds.

[0189] Test Procedure

[0190] A France brand XU112 programmable furnace was set at a temperature of 55° C. The molds filled with compositions A to D were left at this temperature until the polymerization of the compositions was complete. The furnace was then brought to a temperature of 90° C. and the molds were then heated at this temperature for 1 hour. The tensile tests were performed under the conditions presented in table 1 below:

TABLE-US-00001 TABLE 1 Preparation of the test specimens Chopping Charly processor Test conditions Standard (No., type, date) ISO527 type 5A; 5B Temperature (° C.) 23° C. Force sensor (KN) 50 kN Working length (Lo) 25 mm Extensometer Used for calculating the modulus

[0191] Tensile Test Results

[0192] It is observed that the use of a peroxide system comprising a hemiperoxyacetal and a peroxyacetal offers tensile mechanical performance qualities that are higher than implementation under the same conditions but with an organic peroxide of perester type.