Composition comprising an ethylenically unsaturated polymer resin, at least one organic peroxide of formula(i) and at least one organic peroxide of formula (II), and use of the same

Abstract

The present invention relates to a composition comprising an ethylenically unsaturated polymer resin, at least one organic peroxide of formula (I) and at least on organic peroxide of formula (II) and use of the mixture of at least one organic peroxide of formula (I) and at least one organic peroxide of formula (II) for curing of a composition comprising an ethylenically unsaturated polymer resin, in particular for the preparation of a synthetic stone.

Description

[0001] DESCRIPTION

[0002] Title: COMPOSITION COMPRISING AN ETHYLENICALLY UNSATURATED POLYMER RESIN, AT LEAST ONE ORGANIC PEROXIDE OF FORMULA (I) AND AT LEAST ONE ORGANIC PEROXIDE OF

[0003] FORMULA (II), AND USE OF THE SAME

[0004] Field of the invention

[0005] The present invention relates to a composition comprising an ethylenically unsaturated polymer resin, at least one organic peroxide of formula (I) and at least one organic peroxide of formula (II) and use of the mixture of at least one organic peroxide of formula (I) and at least one organic peroxide of formula (II) for curing of a composition comprising an ethylenically unsaturated polymer resin, in particular for the preparation of a synthetic stone.

[0006] Background

[0007] Synthetic stones simulating various natural stones such as marble, quartz or granite are commonly used in the industry. By way of example, synthetic stones are used for the manufacture of various shaped articles such as floor, internal or external walls, tiles, countertops, sinks, table tops or architectural facings.

[0008] Synthetic stones are typically made from a composition comprising polymer resins, reactive monomers, mineral fillers, curing agents and other compounds such as coupling agents, and colorants.

[0009] Polymer resins offer good mechanical and chemical properties, weather resistance and low cost. Furthermore, polymer resins are easy to handle and can be pigmented, which is advantageous for the preparation of synthetic stone shaped articles.

[0010] The conversion of the composition from liquid to solid results from the cross-linking reaction involving the polymer resin and optional reactive monomers to form a three-dimensional network. A notable example of the reactive monomer used in this frame is styrene. (Meth)acrylic monomers are also sometimes used, especially methyl methacrylate. Curing agents are generally needed to induce the cross-linking reaction of the polymer resin itself or with the reactive monomer. Curing agents frequently used in the art notably encompass organic peroxides.

[0011] The curing agents play a key role in the curing of resin compositions. For example, some curing agents can lead to a high curing rate which is favourable from a production efficiency standpoint. However, usually fast curing may easily lead to defective products as the curing reaction is exothermic and too high temperatures in the composite curing process may generate internal stress and cracks in the final material. This can be particularly detrimental in the preparation of synthetic stones.

[0012] Accordingly, there is a need for a novel curing agent for resin curing process, which can achieve a desired curing rate, a relatively low exothermic temperature, and also a relatively low content of residual monomers in the cured resin, so that the cured resin can be produced in a high efficiency and cracks and deformation issue can be avoided.

[0013] Summary of the invention

[0014] In the first aspect, the present invention provides a composition, comprising:

[0015] - an ethylenically unsaturated polymer resin, optionally in combination with an ethylenically unsaturated monomer;

[0016] - at least one organic peroxide of formula I:

[0017] [Chem 1] wherein,

[0018] Ri represents linear or branched C1-C20, preferably C3-C9 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I, and -OOC(O)R2'; R2 represents linear or branched C1-C20, preferably C4-C9 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I; and

[0019] R2' represents linear or branched C1-C20, preferably C4-C9 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I; and R2' is the same as or different from R2,

[0020] - at least one organic peroxide represented by formula II, wherein the formula II has the following structure:

[0021] [Chem 2]

[0022] Rs and R4 are the same or different from each other and each is independently selected from the group consisting of linear or branched C1-C20, preferably C1-C10, preferably C1-C5 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I; and

[0023] Rsa, Rsb, and Rscare the same or different from each other and each is independently selected from the group consisting of H, or linear or branched C1-C10, preferably C1-C5, preferably Cl- C3 alkyl, alkenyl or alkynyl, preferably methyl, ethyl, or linear or branched C3 alkyl, preferably H, or methyl.

[0024] In the second aspect, the present invention relates to the use of a mixture comprising at least one organic peroxide of formula (I) and at least one organic peroxide of formula (II) for curing of a composition comprising an ethylenica lly unsaturated polymer resin.

[0025] In the third aspect, the present invention relates to a method of curing a composition according the invention, comprising a step of heating the composition at a temperature ranging from 70 to 100°C, more preferably from 75 to 95°C, more preferably from 80 to 92°C and even more preferably from 82 to 90°C.

[0026] In the fourth aspect, the present invention relates to an article, in particular synthetic stone, obtainable by the method of the invention.

[0027] The inventors have surprisingly found that a balance of fast curing and low exothermic temperature can be achieved by using a specific mixture of organic peroxides. With the present composition, it is possible to prepare, in a relatively high productivity (or production efficiency), cured product (such as synthetic stones) which are free of cracks and deformation issues and having low content of residual monomer, and thus having improved mechanical properties.

[0028] Detailed description of the invention

[0029] The terminology used herein is for the purpose of describing one or more exemplary embodiments only and is not intended to be limiting. Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this general inventive concept belongs.

[0030] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. For example, "a curing agent" has the same meaning as "at least one curing agent" and "one or more curing agents", unless the context clearly indicates otherwise.

[0031] It will be further understood that the terms "comprising", "comprise(s)" as used herein are synonymous with "including", "include(s)" or "containing", "contains". The terms "comprise(s)" and / or "comprising," or "include(s)" and / or "including" when used in this specification, specify the presence of stated features (members, components, method steps or the like), but do not preclude the presence or addition of one or more other non-recited features. The terms "comprising", "comprises" also include the term "consisting of".

[0032] The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1, 2, 3, 4, 5 when referring to, for example, a number of elements, and can also include, e.g., 1.5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of numerical ranges by end points also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein

[0033] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art.

[0034] Preferred features and embodiments of the invention are set herein below. Any feature indicated as being preferred or advantageous may be combined with any other feature or features or statements indicated as being preferred or advantageous.

[0035] Composition

[0036] The present invention relates to a composition, comprising:

[0037] - an ethylenically unsaturated polymer resin, optionally in combination with an ethylenically unsaturated monomer;

[0038] - at least one organic peroxide of formula I:

[0039] [Chem 1] wherein,

[0040] Ri represents linear or branched C1-C20, preferably C3-C9 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I, and -OOC(O)R2';

[0041] R2represents linear or branched C1-C20, preferably C4-C9 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I; and

[0042] R2' represents linear or branched C1-C20, preferably C4-C9 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I; and R2' is the same as or different from R2, and

[0043] - at least one organic peroxide represented by formula II, wherein the formula II has the following structure:

[0044] [Chem 2] wherein,

[0045] Rs and R4 are the same or different from each other and each is independently selected from the group consisting of linear or branched C1-C20, preferably C1-C10, preferably C1-C5 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I; and

[0046] Rsa, Rsb, and Rscare the same or different from each other and each is independently selected from the group consisting of H, or linear or branched C1-C10, preferably C1-C5, preferably Cl- C3 alkyl, alkenyl or alkynyl, preferably methyl, ethyl, or linear or branched C3 alkyl, preferably H, or methyl.

[0047] Preferably, the at least one organic peroxide of formula (I) has a 1 minute half-life temperature (HLT lmin) of 90-130°C, preferably 110-130°C, and more preferably 120-130°C.

[0048] Preferably, the at least one organic peroxide of formula (II) has a 1 minute half-life temperature (HLT(lmin) of 140-170°C, preferably 145-166°C, and more preferably 150-160°C.

[0049] "1 minute half-life temperature" or "HLT lmin" means a temperature at which the half life is one minute. In other words, HLT lmin is the temperature at which a loss of one-half of the organic peroxide occurs after one minute. Usually, the HLT lmin of the organic peroxides is determined by measuring the decomposition rate in n- decane or n-dodecane.

[0050] Preferably, the at least one organic peroxide of formula (I) represents 40-95% by weight, preferably 50-95% by weight, preferably 70-90% by weight, preferably 75-85% by weight, with respect to total weight of the at least one organic peroxide of formula (I) and the at least one organic peroxide of formula (II).

[0051] Preferably, the at least one organic peroxide of formula (II) represents 5-60% by weight, preferably 5-50% by weight, preferably 10-30% by weight, preferably 15-25% by weight, with respect to total weight of the at least one organic peroxide of formula (I) and the at least one organic peroxide of formula (II).

[0052] Preferably, the organic peroxide of formula (I) represents from 40 to 95% by weight, preferably from 50 to 95% by weight, preferably from 70 to 90% by weight, preferably from 75 to 85% by weight, and the organic peroxide of formula (II) represents from 5 to 60% by weight, preferably from 5 to 50% by weight, preferably from 10 to 30% by weight, preferably from 15 to 25% by weight, relative to the total weight of the at least one organic peroxide of formula (I) and the at least one the organic peroxide of formula (II).

[0053] The first organic peroxide can be represented by formula I:

[0054] [Chem 1] wherein,

[0055] Ri represents linear or branched C1-C20 , preferably C3-C9 (e.g., C3, C4, C5, C6, C7, C8, C9) alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, CIO) cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I, and -OOC(O)R2';

[0056] R2 represents linear or branched C1-C20 , preferably C4-C9 (e.g., C4, C5, C6, C7, C8, C9) alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, CIO) cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I; and

[0057] R2' is as defined above for R2 (that is, R2' represents linear or branched C1-C20 , preferably C4- C9 (e.g., C4, C5, C6, C7, C8, C9) alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, CIO) cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I), and R2' can be the same as or different from R2.

[0058] The second organic represented by formula (II):

[0059] [Chem 2]

[0060] (ID wherein,

[0061] Rs and F are the same or different from each other and each is independently selected from the group consisting of linear or branched C1-C20, preferably C1-C10, preferably C1-C5 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I; and

[0062] Rsa, Rsb, and Rscare the same or different from each other and each is independently selected from the group consisting of H, or linear or branched C1-C10, preferably C1-C5, preferably Cl- C3 alkyl, alkenyl or alkynyl, preferably methyl, ethyl, or linear or branched C3 alkyl, preferably H, or methyl. Preferably, the at least one organic peroxide of formula (I) is selected from the group consisting of: tert-butyl peroxyneodecanoate, tert-butyl peroxypivalate, tert-butyl peroxy-2- ethylhexanoate, a-cumyl peroxyneodecanoate, 2,5-dimethyl-2,5-di-(2-ethylhexanoyl peroxy)- hexane,tert- amyl peroxyneodecanoate, tert-amyl peroxypivalate, tert-amyl peroxy-2- ethylhexanoate,l,l-dimethyl-3-hydroxybutyl peroxyneodecanoate, 1,1, 3, 3-tetramethylbutyl peroxy-2-ethylhexanoate, 1,1, 3, 3-tetramethylbutyl peroxyneodecanoate, and combination thereof, preferably the organic peroxide of formula (I) is tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, and mixtures thereof.

[0063] Preferably, the at least one organic peroxide of formula (I) is selected from the group consisting of tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, and mixtures thereof.

[0064] Preferably, the at least one organic peroxide of formula (II) is selected from the group consisting of l-(tert-amylperoxy)-l-(methylperoxy) cyclohexane, l,l-di-(tert-amylperoxy)-cyclohexane, l,l-di-(tert-amylperoxy)-3,3,5-trimethylcyclohexane, l,l-di-(tert-butylperoxy)-3,3,5- trimethylcyclohexane, l,l-di-(tert-butylperoxy)cyclohexane and mixtures thereof.

[0065] Preferably, the second organic peroxide can be selected in the group consisting of: 1, l-di-(tert- butylperoxy)cyclohexane, l,l-di-(tert-amylperoxy)-cyclohexane and combination thereof.

[0066] The composition can be formulated in presence or absence of solvent. In other words, the composition can comprise a solvent or no solvent.

[0067] The solvent can be of any type known to one of skill in the art suitable for solvating / disolving said organic peroxides (the first and second organic peroxides). Preferably, the solvent is an organic solvent selected from the group consisting of an (aliphatic, cycloaliphatic and / or aromatic) ketone solvent, an (aliphatic, cycloaliphatic and / or aromatic) hydrocarbon solvent, an (aliphatic, cycloaliphatic and / or aromatic) ether solvent, an (aliphatic, cycloaliphatic and / or aromatic) ester solvent, an (aliphatic, cycloaliphatic and / or aromatic) alcohol solvent, and a mineral oil. For example, the solvent is selected form the group consisting of dimethyl phthalate, dimethyl tetraphthalate, methyl isobutyl ketone, cyclohexanone, ethyl acetate, isododecane, or a combination thereof.

[0068] However, the composition exhibits excellent storage stability (e.g., at room temperature) even in absence of solvent.

[0069] Preferably, the composition comprises no solvent.

[0070] Compared with peroxide ketone curing system of the prior art, the composition of the invention leads to higher curing efficiency. Higher curing degree and hardness can be obtained, and the odor of final product (mainly due to high content of residual monomers) can be reduced at the same time. Moreover, the composition of the invention can result in very little, even no peroxide residue in final cured products and thus avoid product discoloration caused by peroxide residence.

[0071] The composition of the invention can further includea filler, preferably one or more selected from the group consisting of quartz powder, quartz sand, glass particle, glass fiber, carbon fibre, fiber fabric, AI(OH)s particle, and CaCCh particle.

[0072] The composition of the invention can further include a coupling agent, preferably silane coupling agent.

[0073] The composition of the invention can further include a curing accelerator, preferably curing accelerator based on Co, Cu, Mn, or Fe salts or complexes.

[0074] The composition of the invention can further include a colorant.

[0075] Preferably, the total content of the organic peroxide of formula (I) and the organic peroxide of formula (II) is comprised between 0.5 and 5wt%, preferably between 0.5 and 2 wt% based on the total weight of the composition.

[0076] By "the total content of the organic peroxide of formula (I) and of the organic peroxide of formula (II)" it is meant the sum of the content of the organic peroxide of formula (I) and the content of the organic peroxide of formula (II).

[0077] The ethylenically unsaturated polymer resin (also referred to as first polymer resin) can be liquid, semisolid or solid at room temperature. For example, the liquid ethylenically unsaturated polymer resin can have a dynamic viscosity at room temperature (25°C) in a range from 10 mPa*s to 10000 mPa*s, preferably from 20 mPa*s to 7000 mPa*s and advantageously from 20 mPa*s to 5000 mPa*s and more advantageously from 20 mPa*s to 2000 mPa*s and even more advantageously between 20mPa*s and 1000 mPa*s. The viscosity can be easily measured with a Rheometer or viscosimeter. If the liquid resin has a Newtonian behaviour, meaning no shear thinning, the dynamic viscosity is independent of the shearing in a rheometer or the speed of the mobile in a viscometer. If the liquid resin has a non-Newtonian behaviour, meaning shear thinning, the dynamic viscosity is measured at a shear rate of Is1at 25°C.

[0078] In an embodiment, the ethylenically unsaturated polymer resin comprises one or more ethylenically unsaturated polymer resins.

[0079] Preferably, the ethylenically unsaturated polymer resin can comprise or be one or more selected from the group consisting of unsaturated polyester resin, an (meth)acrylic resin, a vinyl ester resin and any combination thereof.

[0080] Preferably, the ethylenically unsaturated polymer resin can comprise or be one or more selected from the group consisting of unsaturated polyester resin, a vinyl ester resin and any combination thereof.

[0081] Preferably, the ethylenically unsaturated polymer resin can comprise or be one or more unsaturated polyester resins.

[0082] The ethylenically unsaturated polymer resin can be used in combination with one or more types of an ethylenically unsaturated monomer (also referred as reactive monomer). In other words, the composition can further comprise one or more types of an ethylenically unsaturated monomer. When used, the ethylenically unsaturated monomer can function as a reactive "diluent" which can help crosslinking reactions during curing process. In formulation of the composition, the ethylenically unsaturated monomer can be added separately from the ethylenically unsaturated polymer resin. Alternatively, the ethylenically unsaturated monomer and the ethylenically unsaturated polymer resin can be provided in the form of a mixure (prepared in advance) to formulate the composition. Alternatively, a part of the ethylenically unsaturated monomer (first part) can be provided in the form of a mixture with the ethylenically unsaturated polymer resin, and the mixure and the remaining part of the ethylenically unsaturated monomer (second part) (the ethylenically unsaturated monomer contained in the second part may be the same as or different from that contained in the first part) are used to formulate the composition. The mixure as mentioned above of the ethylenically unsaturated monomer with the ethylenically unsaturated polymer resin may be commercially available or self-prepared.

[0083] The ethylenically unsaturated monomer can be of any type known to one of skill in the art, for example, the ethylenically unsaturated monomer can comprise ethylenically unsaturated compounds including one or more of vinylic groups, (meth)acrylic groups, and allylic groups. Preferably, the ethylenically unsaturated monomer can comprise or be one or more selected from the group consisting of a vinylic monomer, an (meth)acrylic monomer, an allylic monomer, or any combination thereof.

[0084] Examples of the vinylic monomer include, but not limited to a styrenic compound or styrene- based compound, such as styrene, methyl styrene, p-chlorostyrene, t-butyl styrene, divinylbenzene or bromostyrene, vinyl naphthalene, divinyl naphtalene, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl ether and divinyl ether.

[0085] Examples of the (meth)acrylic monomer include, but not limited to methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, phenyl acrylate, phenyl methacrylate, benzyl acrylate and benzyl methacrylate.

[0086] Examples of the allylic monomer include, but not limited to allyl phthalate, diallyl phthalate, diallyl isophthalate, triallyl cyanurate and diallyl terephthalate.

[0087] The unsaturated polyester resin can be obtained by condensation of one or more acid monomers and / or one or more acid anhydride monomers with one or more polyol monomers, provided that at least one of the components comprises an ethylenic unsaturation. More preferably, the unsaturated polyester resin can be obtained by condensation of one more polycarboxylic acid (e.g., dicarboxylic acid) monomers and / or one or more polycarboxylic acid anhydride (e.g., dicarboxylic acid anhydride) monomers and one or more glycol monomers, provided that at least one of the components comprises an ethylenic unsaturation.

[0088] The acid monomer can be of any type known to one of skill in the art. In an embodiment, the acid monomer can be a dicarboxylic acid monomer, e.g., one or more selected from the group consisting of phthalic acid, isophthalic acid, terephthalic acid, maleic acid, oxalic acid, malonic acid, tetrahydrophthalic acid, hexahydrophthalic acid, succinic acid, sebacic acid, azelaic acid, adipic acid and fumaric acid.

[0089] The acid anhydride monomer can be of any type known to one of skill in the art. In an embodiment, the acid anhydride monomer can be a dicarboxylic acid anhydride monomer, e.g., one or more selected from the group consisting of phthalic anhydride, isophthalic anhydride, terephthalic anhydride, maleic anhydride, oxalic anhydride, malonic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, sebacic anhydride, azelaic anhydride, adipic anhydride and fumaric anhydride.

[0090] The polyol can be of any type known to one of skill in the art. In an embodiment, the polyol can be a glycol, e.g., one or more selected from the group consisting of an aliphatic diol and an aromatic diol. In an embodiment, the polyol can be one or more selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, pentylene glycol, hexylene glycol and neopentylene glycol.

[0091] Preferably, the unsaturated polyester resin is o-benzene or m-benzene type unsaturated polyester resin. Preferably, the o-benzene or m-benzene type can have a curing temperature in the range of 70-100°C.

[0092] The vinyl ester resin can be obtained by condensation of one or more polyepoxide with one or more monocarboxylic acid monomer having an ethylenic unsaturation.

[0093] The polyepoxide can be of any type known to one of skill in the art. The polyepoxide is preferably selected from the group consisting of glycidyl polyethers of polyhydric alcohols and glycidyl polyethers of polyhydric phenols. The polyhydric alcohols can be one or more selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, pentylene glycol, hexylene glycol and neopentylene glycol. The polyhydric phenols can be one or more selected from the group consisting of hydroquinone, resorcinol, bishenol A, bishenol S, bishenol F.

[0094] The monocarboxylic acid monomer can be of any type known to one of skill in the art. In an embodiment, the monocarboxylic acid monomer can be one or more selected from the group consisting of acrylic acid, methacrylic acid, ethylacrylic acid, propylacrylic acid, isopropylacrylic acid, butylacrylic acid, isobutylacrylic acid, phenylacrylic acid, benzylacrylic acid, halogenated acrylic acid, and cinnamic acid.

[0095] The ethylenically unsaturated polymer resin plus the optional ethylenically unsaturated monomer content is comprised between 5 and 45 wt%, preferably 7 and 30wt%, and even more preferably comprised between 10 and 20 wt% based on the total weight of the composition.

[0096] Preferably, the composition comprises an ethylenically unsaturated monomer (e.g., styrene) in an amount from 0 to 50% by weight, with respect to the total weight of the ethylenically unsaturated polymer resin and the ethylenically unsaturated monomer.

[0097] Optionally, the composition may further comprise a saturated or essentially saturated resin (second resin). Said second resin may be, but not limited to: a polymer (homopolymer or copolymer) derived from one or more selected from the group consisting of olefins such as ethylene, propylene, the vinylic monomer, the (meth)acrylic monomer, the allylic monomer as described above. For example, said second resin may be polyolefins such as polyethylene, polypropylene, copolymer and / or blend thereof. For another example, said polymer can be a polymer (homopolymer or copolymer) derived from one or more selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, phenyl acrylate, phenyl methacrylate, benzyl acrylate and benzyl methacrylate. Said polymer can also be a blend of any two polymers as described herein.

[0098] The saturated or essentially saturated resin (second resin) may be present in the composition in an amount of 0 to 20 wt% , based on the total weight of the composition.

[0099] When the saturated or essentially saturated resin (second resin) is present, the sum of amounts of the ethylenically unsaturated monomer, the ethylenically unsaturated polymer resin (first resin) and the saturated or essentially saturated polymer resin (second resin) may be in the range of 5 to 45 wt% , based on the total weight of the composition.

[0100] Preferably, the composition can further comprise a filler. The filler can be of any type known to one of skill in the art. The filler can include, but not limited to, one or more selected from the group consisting of quartz powder, quartz sand, glass particle, glass fiber, carbon fibre, fiber fabric, AI(OH)s particles , and CaCCh particles.

[0101] The average particle size of the filler may be in the range of 1 to 2000pm, preferably 10 to 1000 pm, preferably 100 to 500 pm, or a range defined by any two of the forgoing values. Alternatively, the average particle size of the filler may be in the range of 10 to 1000 mesh size, preferably 20 to 500 mesh size.

[0102] The filler may have a mono-modal or multi-modal (e.g., bi-modal or tri-modal or the like) particle size distribution.

[0103] In a preferable embodiment, the filler can have the particle size distribution as defined below: - 10 to 50wt%, preferably 20-40wt%, preferably 25-35wt% of the filler has a particle size in the range of 10 to less than 40 mesh size, relative to the total weight of filler in the composition;

[0104] - 20 to 70wt%, preferably 30-60wt%, preferably 40-50wt% of the filler has a particle size in the range of 40-80 mesh size, relative to the total weight of filler in the composition; and

[0105] - 10 to 40wt%, preferably 15-35wt%, preferably 20-30wt% of the filler has a particle size in the range of greater than 80 to 120 mesh size, relative to the total weight of filler in the composition, with the sum of the three fractions being 100wt%.

[0106] The filler may be present in the composition in an amount of 50 to 90 wt%, preferably 80 to 90wt% based on the total weight of the composition.

[0107] In an embodiment, the composition can further comprise a coupling agent.

[0108] The coupling agent can be of any type known to one of skill in the art. However, it is preferred that the coupling agent is a silane coupling agent, preferably of the following formula: SiXfR ) (Ri3)(Ri4), wherein

[0109] - X represents a vinyl group, an epoxy group, an amino group, a methacryloxy group or an acryloxy group; and

[0110] - R12, R13 and Ru are the same as or different from each other and each independently represents an alkoxy group having from 1 to 6 (e.g., 1, 2, 3, 4, 5, 6) carbon atoms or an alkyl group having from 1 to 6 (e.g., 1, 2, 3, 4, 5, 6) carbon atoms.

[0111] Preferably, the silane coupling agent is selected from the group consisting of a vinyl silane such as vinyltrimethoxysilane and vinyltriethoxysilane, a methacryloxy silane such as 3- methacryloxypropyl methyldimethoxy silane, 3-methacryloxypropyltrimethoxysilane, 3- methacryloxypropyl methyldiethoxysilane and 3-methacryloxypropyl triethoxy silane, an acryloxy silane such as 3-acryloxypropyl trimethoxy silane.

[0112] The coupling agent may be present in the composition in an amount of 0.5 to 5.0wt%, preferably 0.5 to 1.0wt% based on the total weight of the composition.

[0113] In an embodiment, the composition may or may not comprise a further solvent except the solvent optionally used in the organic peroxides. In the present application, when a term "solvent" is used, it means said "solvent" is inert to other components in the composition and does not participate in the curing reaction of the composition.

[0114] The further solvent can be of any type known to one of skill in the art suitable for solvating / dissolving said ethylenically unsaturated compound. Preferably, the further solvent is an organic solvent selected from the group consisting of an (aliphatic, cycloaliphatic and / or aromatic) ketone solvent, an (aliphatic, cycloaliphatic and / or aromatic) hydrocarbon solvent, an (aliphatic, cycloaliphatic and / or aromatic) ether solvent, an (aliphatic, cycloaliphatic and / or aromatic) ester solvent, an (aliphatic, cycloaliphatic and / or aromatic) alcohol solvent, and a mineral oil. For example, the solvent is selected form the group consisting of dimethyl phthalate, dimethyl tetraphthalate, methyl isobutyl ketone, cyclohexanone, ethyl acetate, isododecane, or a combination thereof.

[0115] Said further solvent, if used, can be the same as or different from the solvent optionally used in combination with the organic peroxides of the composition. Preferably, if used, said further solvent is the same as the solvent optionally used in combination with the organic peroxides of the composition.

[0116] The solvent (including the solvent optionally used in in combination with the organic peroxides of the composition and said further solvent) can be present in the composition in an amount of 0 to 40wt% based on the total weight of the composition.

[0117] Preferably, the composition does not comprise a further solvent except the solvent optionally used in in combination with the organic peroxides of the composition. Preferably, the composition does not comprise a solvent.

[0118] When an ethylenically unsaturated monomer (reactive monomer) is used, the further solvent as described above can be omitted partly or totally since said ethylenically unsaturated monomer can also function as a "reactive" solvent or diluent. The composition may or may not comprise a curing accelerator.

[0119] The accelerator can be of any type known to one of skill in the art. The accelerator can be selected from the group consisting of metal salts such as cobalt salt, zinc salt, copper salt, iron based compounds, manganese based compounds and amine-based compounds. Said curing accelerator is preferably a curing accelerator based on Co, Cu, Mn, or Fe salts or complexes. However, preferably the composition does not comprise a curing accelerator, since use of the specific combination of curing agents as defined in the first aspect make it possible to cure the composition at a relatively fast curing rate and at the same time with a relatively lower exothermic peak temperature.

[0120] The curing accelerator can be present in the composition in an amount of 0 to 2.0wt%, based on the total weight of the composition.

[0121] In an embodiment, the composition may optionally further comprise a colorant to render the final product prepared therefrom a desirable color.

[0122] The colorant can be of any type known to one of skill in the art. Preferably, the colorant is selected from the group consisting of titanium dioxide, carbon black, cobalt oxide, nickel titanate, molybdenum disulfide, aluminium flakes, iron oxide, zinc oxide, zinc phosphate, organic pigments such as phthalocyanine and anthraquinone derivatives, azo compounds, indigo derivatives, triarylmethane compounds, and polymethine compounds, or any combination thereof.

[0123] The colorant can be present in the composition in an amount of 0 to 2.0wt%, based on the total weight of the composition.

[0124] The composition may further comprise other commonly used additives (such as, but not limited to antioxidant, antistatic agent, dispersant, and the like) depending on its intended purpose.

[0125] In an embodiment, the composition comprises or consists of: - 0.5 to 5 wt%, preferably 0.5 to 2wt% of the organic peroxide of formula (I) + organic peroxide of formula (II) as defined above;

[0126] - 5 to 45 wt%, preferably 8 to 23wt%, of the ethylenically unsaturated polymer resin plus the optional ethylenically unsaturated monomer, preferably the ethylenically unsaturated monomer is present in an amount of 0 to 50% by weight, preferably 5 to 20% by weight, with respect to the total weight of the ethylenically unsaturated polymer resin and the ethylenically unsaturated monomer;

[0127] - 50 to 90 wt%, preferably 75 to 90wt% of the filler,

[0128] - 0.5 to 5.0wt%, preferably 0.5 to 1.0wt% of the coupling agent;

[0129] - 0 to 40 wt%, preferably 0 wt% of the solvent;

[0130] - 0 to 2 wt%, preferably 0 wt% of the curing accelerator; and

[0131] - 0 to 2 wt%, preferably 0-lwt% of the colorant, based on the total weight of the composition.

[0132] Preferably, the composition is a thermosetting composition, which can in particular be formed in a desired shape (such as by being placed in a mold with desired shape) and cured to yield an article, preferably synthetic stone shaped article.

[0133] The composition can be prepared via any suitable method which can lead to homogeneous mixing of the components of the composition and does not cause a polymerization of the composition or does not degrade the ethylenically unsaturated compound or the organic peroxides contained therein. For example, the composition, whether containing a solvent or not, can be prepared by directly mixing all of the components together, or by mixing some components first, and then mixing the resultant with the remaining components. When the composition contains no solvent, the composition can alternertively be prepared by mixing all of the components together in a solvent to prepare a mixture and then removing the solvent from the mixture; or by mixing some components first in a solvent, and then mixing the resultant with the remaining components to prepare a mixture, and then removing the solvent from the mixture.

[0134] By use of the organic peroxides of the invention, the composition can exhibit during curing an exothermic peak temperature of, for example, below 93°C (i.e., 93°C or lower)(e.g., below 92.5, 92.0, 91.5, 91.0, 90.5, or even 90°C) and a time to the peak temperature in the range of 2700s to 3600s at a curing temperature of 82 to 90°C, e.g., 85°C. Said lower peak temperature during curing is beneficial to avoid cracks and deformation of the final products and thus improve mechanical performance of the final products. Said time to peak temprature during curing is beneficial to avoid cracks and deformation of the final products and thus improve mechanical performance of the final products, and at the same time it is beneficial to achieve a good production efficiency and reduce content of residual monomer in the final products.

[0135] Use

[0136] The present invention also relates to the use of a mixture comprising at least one organic peroxide of formula (I) and at least one organic peroxide of formula (II) as defined above for curing of a composition comprising an ethylenically unsaturated polymer resin.

[0137] The present invention also relates to the use of a mixture of at least one organic peroxide of formula (I) and at least one organic peroxide of formula (II) as defined above for curing of a composition comprising an ethylenically unsaturated polymer resin.

[0138] Preferably, said use is for the preparation of an article, preferably the preparation a synthetic stone.

[0139] Preferably, the preparation of the article comprises the following steps:

[0140] - preparation of the composition as defined above,

[0141] - optionally, forming the composition into a desired shape, e.g., by placing the composition in a mold of a desired shape, and

[0142] - subjecting the composition to a temperature allowing curing.

[0143] The composition can be formed into various shapes, in particular by vibration moulding and compression under vacuum. The composition is then submitted to a temperature allowing the curing reaching a synthetic stone in the desired form. The synthetic stone may then be cooled and eventually polished, and possibly cutted. Preferably the temperature allowing curing (or curing temperature) according to the invention is from 70 to 100°C, more preferably from 75 to 95°C, even more preferably from 80 to 92°C. More preferably, the curing temperature is from 82 to 90°C.

[0144] Preferably, when the composition according to the invention contains styrene, then a low content of residual styrene is obtained in the final article.

[0145] Preferably, the synthetic stone according to the invention 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.

[0146] Examples of shaped articles of synthetic stone produced according to the invention include external and internal walls, table tops, architectural facing, light fixture, bathroom articles, sinks, floor, tiles and countertops.

[0147] Method

[0148] The present invention also relates to a method of curing a composition as defined above, comprising a step of heating the composition at a temperature ranging from 70 to 100°C, more preferably from 75 to 95°C, more preferably from 80 to 92°C and even more preferably from 82 to 90°C.

[0149] Article

[0150] The present invention also relates to an article, in particular synthetic stone, obtainable by the method as defined above.

[0151] Examples

[0152] Raw materials

[0153] Unsaturated polyester resin: DL-901, supplied by AOC; Quartz sand (filler): <40 meshes: 30wt%, 40-80 meshes: 45wt%, 80-120 meshes: 25wt%;

[0154] Coupling agent: 3-methacryloxypropyltrimethoxysilane, KH570 supplied by Dow; and

[0155] Organic peroxides, as shown in the following table. table 1]

[0156] The following examples and comparative examples were performed with the following composition : unsaturated polyester resin: 15wt%; quartz sand: 85wt%; organic peroxide curing agents (OP): 0.8phr (with respect to 100 phr of the total weight of unsaturated polyester resin and the quartz sand); and coupling agent: 0.8phr (with respect to 100 phr of the total weight of unsaturated polyester resin and the quartz sand)

[0157] Curable compostions and curing process:

[0158] All raw materials were mixed at room temperature and then loaded into the mold. After a cold pressing under 40 bar for 5 min, a curing process was carried out in oven at 85°C for 1 hour. A thermocouple was used to record the heat release during the curing process, and T peak (time to peak temperature) (s) and exothermic peak temperature (°C) were recorded. T peak (s) means the time spent from start of the curing process to the timing of reaching exothermic peak.

[0159] Test of residual monomer (ppm): grind the cured resin into powder, and take lg powder into which 10 ml chloroform is added. After sonicating for 2 hours, the sample is subjected to gas chromatography (GC) test with Agilent 7890B.

[0160] [Table 2]

[0161]

[0162] OP* : the ratio listed in column "OP" is a ratio by weight

[0163] In the curing process, a low exothermic peak temperature (°C) and a T peak (s) in a range of 2700s to 3600s are desirable, more preferably in a range of 3000s to 3300s. The curing process is exothermic. A high exothermic temperature may generate internal pressure and lead to cracks or deformation in the cured resin. In addition, T peak is an indicator of curing speed. If the T peak (s) is low, such as lower than 2700s, it means that the curing process is super fast and usually leads to weak mechanical property, for example, the cured resin is easy to crack even during curing process (cracking issue). If the T peak (s) is high, such as higher than 3600s, it means the curing process is slow and the production efficiency is low. A high residual monomer wt% means a low curing degree and may cause low mechanical property.

[0164] From the above tables, it can be seen that in Examples 1-6 according to the present invention, the T peaks are within the range of 2700s to 3600s, indicating the curing occurred fast without cracking issue. Furthermore, in Examples 1-6, the exothermic peak temperatures are low, i.e., around 90°C. However, in Comparative examples 1 or 2 where only one curing agent is used, the T peak is low and a cracking issue which is undesired is caused. In Comparative Examples 3 or 4 where only another curing agent is used, the T peak is high which means slow curing rate and low production efficiency. In Comparative Example 5 where a mixture of 2 organic peroxides not according to the invention is used, the exothermic peak is higher than those in Examples 1-6, indicating higher risk of generation of internal pressure and cracks or deformation in the final products.

[0165] While the invention has been particularly shown and described with reference to embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit or scope of the invention as defined by the following claims.

Claims

CLAIMS1. Composition, comprising:- an ethylenically unsaturated polymer resin, optionally in combination with an ethylenically unsaturated monomer;- at least one organic peroxide of formula I:[Chem 1]wherein,Ri represents linear or branched C1-C20, preferably C3-C9 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I, and -OOC(O)R2';R2represents linear or branched C1-C20, preferably C4-C9 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I; andR2' represents linear or branched C1-C20, preferably C4-C9 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I; and R2' is the same as or different from R2, and- at least one organic peroxide of formula II, wherein the formula II has the following structure: [Chem 2]wherein,Rs and R4 are the same or different from each other and each is independently selected fromthe group consisting of linear or branched C1-C20, preferably C1-C10, preferably C1-C5 alkyl, alkenyl or alkynyl, preferably alkyl, which is unsubstituted or substituted by one or more substituents selected from the group consisting of C3-C10 cycloalkyl, phenyl, hydroxyl, amino, halogen such as F, Cl, Br or I; andRsa, Rsb, and Rscare the same or different from each other and each is independently selected from the group consisting of H, or linear or branched C1-C10, preferably C1-C5, preferably Cl- C3 alkyl, alkenyl or alkynyl, preferably methyl, ethyl, or linear or branched C3 alkyl, preferably H, or methyl.

2. The composition of claim 1, wherein the organic peroxide of formula (I) represents from 40 to 95% by weight, preferably from 50 to 95% by weight, preferably from 70 to 90% by weight, preferably from 75 to 85% by weight, and the organic peroxide of formula (II) represents from 5 to 60% by weight, preferably from 5 to 50% by weight, preferably from 10 to 30% by weight, preferably from 15 to 25% by weight, relative to the total weight of the at least one organic peroxide of formula (I) and the at least one the organic peroxide of formula (II).

3. The composition of any one of claims 1 or 2, wherein the at least one organic peroxide of formula (I) is selected from the group consisting of: tert-butyl peroxyneodecanoate, tert-butyl peroxypivalate, tert-butyl peroxy-2-ethylhexanoate, a-cumyl peroxyneodecanoate, 2, 5- dimethyl-2,5-di-(2-ethylhexanoyl peroxy)-hexane, tert- amyl peroxyneodecanoate, tert-amyl peroxypivalate, tert-amylperoxy-2-ethylhexanoate, l,l-dimethyl-3-hydroxybutyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 1, 1,3,3- tetramethylbutyl peroxyneodecanoate and combination thereof, preferably the organic peroxide of formula (I) is selected from the group consisting of tert-butyl peroxy-2- ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate and mixtures thereof.

4. The composition of any one of claims 1 to 3, wherein the least one organic peroxide of formula (II) is selected from the group consisting of l-(tert-amylperoxy)-l-(methylperoxy) cyclohexane, l,l-di-(tert-amylperoxy)-cyclohexane, l,l-di-(tert-amylperoxy)-3,3,5- trimethylcyclohexane, l,l-di-(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1, l-di-(tert- butylperoxy)cyclohexane and mixtures thereof.

5. The composition according to any of the proceedings claims, comprising a filler, preferably one or more selected from the group consisting of quartz powder, quartz sand, glass particle, glass fiber, carbon fibre, fiber fabric, AI(OH)s particle, and CaCCh particle;- optionally, a coupling agent, preferably silane coupling agent;- optionally, a solvent;- optionally, a curing accelerator, preferably curing accelerator based on Co, Cu, Mn, or Fe salts or complexes; and- optionally, a colorant.

6. The composition according to any of the proceedings claims, wherein the ethylenically unsaturated polymer resin is one or more selected from the group consisting of unsaturated polyester resin, an (meth)acrylic resin and a vinyl ester resin.

7. The composition of claim 6, wherein the unsaturated polyester resin is o-benzene or m- benzene type unsaturated polyester resin.

8. The composition of claim 1 to 5, wherein the ethylenically unsaturated monomer is one or more selected from the group consisting of a vinylic monomer, an (meth)acrylic monomer, an allylic monomer, and any combination thereof.

9. The composition of any one of the proceeding claims, wherein the total content of the organic peroxide of formula (I) and of the organic peroxide of formula (II) is comprised between 0.5 and 5wt%, preferably 0.5 to 2 wt% based on the total weight of the composition.

10. The composition of any one of the proceeding claims, wherein the content of the ethylenically unsaturated polymer resin plus the optional ethylenically unsaturated monomer content is comprised between 5 and 45 wt%, preferably 7 and 30wt%, and even more preferably comprised between 10 and 20 wt% based on the total weight of the composition.

11. The composition of any one of the proceeding claims, wherein the ethylenically unsaturated monomer is present in an amount of 0 to 50% by weight, preferably 5 to 20% by weight, with respect to the total weight of the ethylenically unsaturated polymer resin and the ethylenically unsaturated monomer.

12. The composition of any one of the proceeding claims, wherein the at least one organic peroxide of formula (I) has a 1 minute half-life temperature (HLT lmin) of 90-130°C, preferably 110-130°C, and more preferably 120-130°C.

13. The composition of any one of the proceeding claims, wherein the at least one organic peroxide of formula (II) has a 1 minute half-life temperature (HLT(lmin) of 140-170 °C , preferably 145-166°C, and more preferably 150-160°C.

14. Use of a mixture comprising at least one organic peroxide of formula (I) and at least one organic peroxide of formula (II) as defined in of any one of claims 1 to 13 for curing of a composition comprising an ethylenically unsaturated polymer resin.

15. The use of claim 14, for the preparation of an article, preferably the preparation a synthetic stone.

16. Method of curing a composition as defined in any of claims 1 to 13, comprising a step of heating the composition at a temperature ranging from 70 to 100°C, more preferably from 75 to 95°C, more preferably from 80 to 92°C and even more preferably from 82 to 90°C.

17. Article, in particular synthetic stone, obtainable by the method as defined in claim 16.

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