COBALT FREE PREPROMOTED UNSATURATED POLYESTER RESIN SYSTEM FOR ENGINEERED STONE

Abstract

The invention relates to a formable composition for the preparation of engineered stone comprising a cobalt free prepromoted unsaturated polyester resin system, an inorganic particulate material and a peroxide component. The invention also relates to a method for the preparation of engineered stone as well as to the use of the cobalt free prepromoted unsaturated polyester resin system for the preparation of engineered stone.

Claims

1. A formable composition for the preparation of engineered stone comprising (A) a cobalt free prepromoted unsaturated polyester resin system comprising (i) a unsaturated polyester resin component; (ii) a metal catalyst capable of catalyzing curing of said unsaturated polyester resin component; (iii) a quaternary ammonium salt; and (iv) optionally, one or more additives selected from the group consisting of reactive diluents, accelerators, co-promoters, dispersing agents, UV absorbers, stabilizers, inhibitors and rheology modifiers; (B) an inorganic particulate material; and (C) a peroxide component.

2. The composition according to claim 1, wherein the metal catalyst comprises zinc or copper.

3. The composition according to claim 1 or 2, wherein the quaternary ammonium salt is a benzyl-N,N,N-trialkylammonium salt or a N,N,N,N-tetraalkylammonium salt.

4. The composition according to any of the preceding claims, wherein the unsaturated polyester resin component is obtained by reacting a mixture comprising a multicarboxylic acid component and a polyhydric alcohol component, wherein the multicarboxylic acid component and/or the polyhydric alcohol component comprises ethylenic unsaturation; wherein preferably the multicarboxylic acid component is selected from the group consisting of aliphatic dicarboxylic acids, aliphatic tricarboxylic acids, aliphatic tetracarboxylic acids, aromatic dicarboxylaic acids, aromatic tricarboxylic acids and aromatic tetracarboxylic acids; and/or wherein preferably the polyhydric alcohol is selected from the group consisting of aliphatic diols, aliphatic triols, aliphatic tetraols, aromatic diols, aromatic triols and aromatic tetraols.

5. The composition according to any of the preceding claims, wherein the unsaturated polyester resin component is a reaction product of a mixture comprising at least 1, 2 or 3 diols selected from the group consisting of propylene glycol, dipropylene glycol, ethylene glycol, and diethylene glycol; and at least 1, 2, 3 or 4 acids selected from the group consisting of maleic acid, isophthalic acid, phthalic acid, and adipic acid, or their acid anhydrides.

6. The composition according to any of the preceding claims, wherein the cobalt free prepromoted unsaturated polyester resin system comprises a reactive diluent selected from the group consisting of styrene, substituted styrene, nono-, di- and polyfunctional esters of monofunctional acids with alcohols or polyols, mono-, di- and polyfunctional esters of unsaturated monofunctional alcohols with carboxylic acids or their derivatives.

7. The composition according to any of the preceding claims, wherein the inorganic particulate material comprises quartz aggregates and/or quartz fillers.

8. The composition according to any of the preceding claims, wherein the inorganic particulate material has a particle size distribution such that about 30 wt.-% to about 70 wt.-% of the particles have a particle size within the range of from about 0.1 m to about 0.3 m; about 5 wt.-% to about 30 wt.-% of the particles have a particle size within the range of from about 0.3 m to about 0.6 m; and about 10 wt.-% to about 40 wt.-% of the particles have a particle size within the range of from about 20 m to about 60 m.

9. The composition according to any of the preceding claims, wherein the peroxide component is cumene hydroperoxide or methyl isobutyl ketone peroxide.

10. The composition according to any of the preceding claims, which has a pot life of at least about 30 minutes.

11. The composition according to any of the preceding claims, wherein the content of the cobalt free prepromoted unsaturated polyester resin system is about 0.1 wt.-% to about 30 wt.-%, relative to the total weight of the formable composition; and/or wherein the content of the inorganic filler material is about 70 wt.-% to about 99.9 wt.-%, relative to the total weight of the formable composition.

12. A method for the preparation of engineered stone comprising the steps of (a) preparing a formable composition by mixing (A) a cobalt free prepromoted unsaturated polyester resin system as defined in any of claims 1 to 6; (B) an inorganic particulate material as defined in any of claim 1, 7 or 8; and (C) a peroxide component as defined in any of claim 1 or 9; (b) forming the composition prepared in step (a) into a desired shape; and (c) allowing the composition formed in step (b) to cure.

13. Engineered stone obtainable by the method according to claim 12.

14. A cobalt free prepromoted unsaturated polyester resin system comprising (i) a unsaturated polyester resin component; (ii) a metal catalyst comprising zinc or copper and being capable of catalyzing curing of said unsaturated polyester resin component; (iii) a benzyl-N,N,N-trialkylammonium salt or a N,N,N,N-tetraalkylammonium salt; and (iv) optionally, one or more additives selected from the group consisting of reactive diluents, accelerators, co-promoters, dispersing agents, UV absorbers, stabilizers and rheology modifiers.

15. Use of a cobalt free prepromoted unsaturated polyester resin system as defined in any of claim 1 to 6 or 14 for the preparation of engineered stone.

Description

EXAMPLE 1

[0131] The following 6 resin compositions were prepared and their pot lifes as well as their curing properties were determined:

TABLE-US-00004 Engineered Stone Polyester Resin [wt.-%] 1-1 1-2 1-3 1-4 1-5 1-6 unsaturated polyester UPR-1 UPR-1 UPR-1 UPR-1 UPR-1 UPR-1 resin component processability at 40 C. 95 min 100 min 360 min >24 hours 130 min >24 hours curing time at 80 C. 9.2 min 9.7 min 11.5 min >50 min 9.7 min 21.2 min (25 C.-PEC) PEC 213.2 C. 211.2 C. 221.1 C. 213.1 C. 217.8 C. metal catalyst.sup.1, 2 0.2% Co 0.2% Zn (8%) + 0.2% Zn 0.2% Zn 0.2% Zn 0.2% Zn (6%) 0.2% Co (6%) (8%) (8%) (8%) (8%) ammonium salt 0.2% 0.2% 0.2% 0.2% 0.2% Empigen Empigen Empigen Empigen Empigen peroxide component 2% 2% CHP 2% CHP 2% TBPB 2% MIKP 2% BPO TBPB .sup.1 percentages without parentheses indicate added amount of composition comprising metal catalyst, relative to the total weight of the resin .sup.2 percentages in parentheses indicate content of metal salt in composition comprising metal catalyst, relative to the total weight of the composition comprising metal catalyst UPR-1 reaction product of a mixture comprising one or more diols selected from the group consisting of propylene glycol, dipropylene glycol, ethylene glycol, and diethylene glycol; and one or more acids selected from the group consisting of maleic acid, isophthalic acid, phthalic acid, and adipic acid, or their acid anhydrides PEC exothermic peak temperature upon curing of unsaturated polyester resin TBPB tert-butyl peroxibenzoate CHP cumene hydroperoxide MIKP methyl isobutyl ketone peroxide BPO benzoyl peroxide Empigen benzyl trialky ammonium salt

[0132] The resin composition according to example 1-1 (comparative) could be processed at 40 C. for only 95 minutes, whereas under identical conditions the resin composition according to example 1-3 (inventive) could be processed for 360 minutes. The resin composition according to example 1-5 (inventive) clearly had a better processability at 40 C. compared to the resin composition according to examples 1-1 and 1-2 (comparative), but not as good as that according to example 3 (inventive).

EXAMPLE 2

[0133] Engineered stone was prepared from a resin composition containing 10 wt.-% resin (UPR-2). The resin was prepromoted with 0.2% Zn 8% and 0.2% of Empigen Bac80. UPR-2 was a reaction product of a mixture comprising one or more diols selected from the group consisting of propylene glycol, dipropylene glycol, ethylene glycol, and diethylene glycol; and one or more acids selected from the group consisting of maleic acid, isophthalic acid, phthalic acid, and adipic acid, or their acid anhydrides; the composition of UPR-2 differed from that of UPR-1 according to example 1.

[0134] Quartz particles having the following particle size distribution were employed: [0135] Quartz 45 microns: 30% [0136] Quartz 0.1-0.3 mm: 25% [0137] Quartz 0.3-0.6 mm: 35%

[0138] The following additional components were added:

[0139] Silane: 2 wt.-% relative to the total weight of the resin;

[0140] TiO.sub.2: 17 wt.-%% relative to the total weight of the resin;

[0141] CHP: 2 wt.-% relative to the total weight of the resin, as a peroxide.

[0142] Slabs of 3 cm thickness were produced and cured under conventional curing conditions (38 minutes at 115 C. inside an oven). After cooling down to room temperature and waiting for 24 hours at room temperature, the slabs were polished.

[0143] The flexural strength of the slabs was 64 MPa and their impact resistance was 7 J.

[0144] 50 square meters of slabs were produced from 400 kg of resin during 4 hours of continuous operation. There was no need to shut down the production line for cleaning, i.e. the processability of the resin composition was >4 hours.

EXAMPLE 3

[0145] A comparative engineered stone polyester resin comprising 0.19% Co (6%) and 1.79 TBPB could be processed at 40 C. for 1 hour 55 minutes.

[0146] Engineered stone polyester resin according to the invention not containing cobalt could be processed at the same conditions for 3.5 hours:

TABLE-US-00005 Engineered stone polyester resin 3-1 3-2 3-3 3-4 unsaturated polyester UPR-3 UPR-3 UPR-3 UPR-3 resin component PEC [ C.] 214 203.7 213.5 221.4 curing time at 80 C. 8.3 8.6 8.9 12 [min] processability at 40 C. 68 12.5 89 110 [min] metal catalyst 0.2 ml Co 0.2% Co 0.2% Zn 0.2% Zn (per 100 g).sup.1,2 (6%) (6%) ammonium salt 0.2% 0.2% (per 100 g) Empigen Empigen peroxide component 2 ml 2% MIKP 2% MIKP 2% CHP (per 100 g) TRIG 93 .sup.1percentages without parentheses indicate added amount of composition comprising metal catalyst, relative to the total weight of the resin .sup.2percentages in parentheses indicate content of metal salt in composition comprising metal catalyst, relative to the total weight of the composition comprising metal catalyst UPR-3 reaction product of a mixture comprising one or more diols selected from the group consisting of propylene glycol, dipropylene glycol, ethylene glycol, and diethylene glycol; and one or more acids selected from the group consisting of maleic acid, isophthalic acid, phthalic acid, and adipic acid, or their acid anhydrides; the composition of UPR-3 differed from that of UPR-1 and UPR-2 according to examples 1 and 2 PEC exothermic peak temperature upon curing of unsaturated polyester resin TRIG 93 commercial product comprising tert-butyl peroxibenzoate (TBPB) CHP cumene hydroperoxide MIKP methyl isobutyl ketone peroxide Empigen benzyl trialky ammonium salt

[0147] The above experimental data demonstrate that the cobalt free compositions according to the invention have unexpected advantages compared to the compositions of the prior art, e.g. compared to the cobalt containing compositions according to EP-A 2 610 227.