CURING AGENT FOR CURING A POLYMER RESIN

Abstract

A curing agent comprising methyl isobutyl ketone peroxide and at least one peroxide.

Claims

1. A curing agent comprising a methyl isobutyl ketone peroxide and at least one organic peroxide of the following formula (I):
R.sub.1OOR.sub.2(I) wherein R.sub.1 represents an alkyl group having from 1 to 30 carbon atoms, an alkylen group having from 2 to 30 carbon atoms, an aryl group having from 3 to 30 carbon atoms or a cycloalkyl group having from 3 to 30 carbon atoms, wherein the alkyl, alkylen, aryl or cycloalkyl group is optionally substituted by an alkyl group having from 1 to 30 carbon atoms, an alkylen group having from 2 to 30 carbon atoms, an aryl group having from 3 to 30 carbon atoms or a cycloalkyl group having from 3 to 30 carbon atoms; and R.sub.2 represents a C(O)R.sub.3, group, a C(O)OR.sub.3 group, a R.sub.3OOR.sub.4 group, an alkyl group having from 1 to 30 carbon atoms, an alkylen group having from 2 to 30 carbon atoms, an aryl group having from 3 to 30 carbon atoms or a cycloalkyl group having from 3 to 30 carbon atoms, wherein the alkyl, alkylen, aryl or cycloalkyl group is optionally substituted by an alkyl group having from 1 to 30 carbon atoms, an alkylen group having from 2 to 30 carbon atoms, an aryl group having from 3 to 30 carbon atoms and a cycloalkyl group having from 3 to 30 carbon atoms, and R.sub.3 and R.sub.4 each independently represents an alkyl group having from 1 to 30 carbon atoms, an alkylen group having from 2 to 30 carbon atoms, an aryl group having from 3 to 30 carbon atoms and a cycloalkyl group having from 3 to 30 carbon atoms, wherein the alkyl, alkylen, aryl or cycloalkyl group is optionally substituted by an alkyl group having from 1 to 30 carbon atoms, an alkylen group having from 2 to 30 carbon atoms, an aryl group having from 3 to 30 carbon atoms and a cycloalkyl group having from 3 to 30 carbon atoms.

2. The curing agent according to claim 1, wherein the organic peroxide of formula (I) has a one hour half life temperature ranging from 100 C. and 140 C.

3. The curing agent according to claim 1, wherein the organic peroxide of formula (I) is represented by the following formula (II):
R.sub.5OOR.sub.6(II) wherein: R.sub.5 represents an alkyl group having from 1 to 6 carbon atoms, and R.sub.6 represents a C(O)R.sub.7, a C(O)OR.sub.7 group or a R.sub.7OOR.sub.8 group, wherein R.sub.7 and R.sub.8 each independently represents an alkyl group having from 1 to 10 carbon atoms, a cycloalkyl group having from 3 to 6 carbon atoms or an aryl group having from 3 to 6 carbon atoms.

4. The curing agent according claim 1, wherein the organic peroxide of formula (I) is selected from the group consisting of tert-butyl peroxybenzoate, OO-tert-butyl-O-(2-ethylhexyl)-monoperoxycarbonate and OO-tert-amyl-O(2ethylhexyl)-monoperoxycarbonate.

5. The curing agent according to claim 1, comprising from 10 to 70% wt of the organic peroxide of formula (I) and from 30 to 90% wt of a methyl isobutyl ketone peroxide, relative to the total weight of the curing agent.

6. The curing agent according to claim 5, comprising about 20% wt of the organic peroxide of formula (I) and about 38% wt of methyl isobutyl ketone peroxide, relative to the total weight of the curing agent.

7. The curing agent according to claim 1, wherein the organic peroxide of formula (I) is liquid at ambient temperature.

8. A composition comprising: at least one polymer resin, at least one mineral filler, and at least one curing agent as defined in claim 1.

9. The composition according to claim 8, comprising from 0.1 to 10% wt of the curing agent of claim 1, relative to the total weight of the composition.

10. The composition according to claim 8, comprising from 0.1 to 50% wt, of the polymer resin relative to the total weight of the composition.

11. The composition according to claim 8, comprising from 30 to 99.3% wt of the mineral filler relative to the total weight of the composition.

12. The composition according to claim 8, wherein the mineral filler is selected from the group consisting of quartz aggregates, quartz particles, quartz powder, marble aggregates, marble particles, marble powder, granite aggregates, granite particles and granite powder.

13. The composition according to claim 8, further comprising at least one additional agent selected from the group consisting of a coupling agent, a colorant, a pigment, an accelerator, an inhibitor, a diluent, a dispersing agent and an UV stabilizer.

14. The composition according to claim 13, comprising from 0.1 to 20% wt of the coupling agent relative to the total weight of the composition.

15. The composition according to claim 13, wherein the coupling agent is a silane.

16. (canceled)

17. (canceled)

18. A method for the preparation of a synthetic stone comprising the steps of: optionally, preparing a composition as defined in claim 8, and optionally, forming the composition into a desired shape, and subjecting the composition to a temperature allowing curing.

19. A synthetic stone obtainable by the method as defined in claim 18.

20. The synthetic stone according to claim 19, wherein the stone is selected from the group consisting of a synthetic metamorphic stone, a synthetic crystalline stone and a synthetic sedimentary stone, in particular a synthetic quartz, a synthetic granite and a synthetic marble.

Description

DESCRIPTION OF THE FIGURES

[0105] FIG. 1 is a graph representing the temperature (vertical axis) of the composition containing Luperox K2 (curve B) and of the composition containing Luperox 26 (curve C) as function of time (horizontal axis).

[0106] FIG. 2 is a graph representing the temperature (vertical axis) of compositions containing the curing agent according to the invention (curve A), Luperox K2 (curve B) and Luperox 26 (curve C) as function of time (horizontal axis).

EXAMPLES

[0107] 1. Materials and Methods

[0108] 1.1. Compositions

[0109] The following compositions were prepared by mixing all the components together (the data presented in table 1 are expressed by weight of components relative to the total weight of composition):

TABLE-US-00001 TABLE 1 Compositions E1, C2 and C3 Composition E1 Composition C2 Composition C3 (according to the (comparative (Comparative Components invention) example) example) Unsaturated 10% 10% 10% polyester resin Mineral filler 85% 85% 85% Silane 2% 2% 2% Curing agent 1% 0% 0% (invention) Luperox 26 0% 1% 0% Luperox K2 0% 0% 1% Luperox26 (Arkema) is a curing agent comprising tert-butylperoxy 2-ethylhexanoate. Luperox K2 (Arkema) is a curing agent comprising methyl isobutyl ketone peroxide.

[0110] The curing agent according to the invention comprises 20% wt of Luperox P (tert-butyl peroxybenzoate) and 80% wt of Luperox K2 (methyl isobutyl ketone peroxide) with respect to the total weight of the curing agent.

[0111] The unsaturated polyester resin results from the polycondensation of anhydride maleic with isophthalic acid and a diol. The unsaturated polyester resin obtained is then dissolved in styrene.

[0112] The mineral filler comprises quartz aggregates, quartz particles and quartz powder with a particle size distribution as defined above: [0113] 55 to 65% wt of the mineral filler have a size particle from 0.075 to 5 mm; and [0114] 20 to 30% wt of the mineral filler have a size particle from 0.005 to 0.045 mm.

[0115] The silane compound is KH570 also known as 3-Methacryloxypropyltrimethoxysilane.

[0116] 1.2. Evaluation of the Curing Properties

[0117] All the raw materials are well blended in a mixer for half an hour. The weight ratio of all raw materials are listed in the above Table 1. The total weight of the composition is 1 kg. Then all the raw materials are placed in a mould. The mould is then placed in an oven at desired temperature. Meanwhile one thermal couple is placed in the middle of the raw materials. The temperature is recorded by a computer (Gelprof 518, Wuhan Jiuwei Composites Company).

[0118] The curing properties of the compositions were analysed at 82 C. and at 90 C. by a temperature probe as function of time.

[0119] After curing, the mould is placed in room temperature to cool down.

[0120] 1.3. Measure of the Residue of Styrene Monomer

[0121] The residues of styrene monomer were measured by Gas Chromatography with Headspace 24 hours after the curing process.

[0122] 2. Results

[0123] 2.1. Curing Properties

[0124] The results are presented in FIGS. 1 and 2, and the following Tables 2 and 3.

TABLE-US-00002 TABLE 2 Curing properties of the compositions E1, C2 and C3 at 82 C. Reaction temperature: Peak Peak Styrene 82 C. time (s) temperature ( C.) residues (ppm) E1 1,109 142.8 20,642 C2 1,031 171.1 6,266 C3 971 146.6 22,249

TABLE-US-00003 TABLE 3 Curing properties of Compositions E1 and C2 at 90 C. Reaction temperature: Peak Peak Styrene 90 C. time (s) temperature ( C.) residues (ppm) E1 837 166.9 5,939 C2 573 173 5,800

[0125] In FIG. 1 and FIG. 2, the peak in the curve coincides with the formation of an insoluble material.

[0126] The results show that the reaction initiated by the curing agent according to the invention occurs at lower temperature. In addition, the slowest curing rate peak time is obtained for the composition E1 containing the curing agent according to the invention.

[0127] This means that the curing rate with the composition according to the invention is slower and thus allows the formation of synthetic stone by minimizing cracking or degradation.

[0128] Besides, when the temperature is 90 C., a low residual styrene content is obtained with the composition E1. This means that the reaction between the unsaturated polyester resin and the styrene in presence of the curing agent according to the invention reaches a high final conversion. Thus the release of residual styrene in the environment is limited leading to less volatile organic compound and less odours.

[0129] At 90 C., the peak temperature obtained for the composition C2 is higher and the peak time is obtained rapidly, this means that the curing rate is faster, the temperature may thus exceed the degradation temperature and this will cause degradation of the synthetic stone.