Copolymers derived from substituted benzpinacols and their use as polymerization initiators

Abstract

The present invention relates to a copolymer comprising (A) allyloxy carboxyl substituted benzopinacol monomers of formula (I) in copolymerized form, and (B) at least one ethylenically unsaturated monomer, and the use of said copolymer as a free radical polymerization initiator. The present invention also relates to allyloxy carboxyl substituted benzopinacols of formula (I).

Description

TECHNICAL FIELD

[0001] The present invention relates to a copolymer derived from a substituted benzopinacol compound, the use of the copolymer as a free radical polymerization initiator and the substituted benzopinacol compound. BACKGROUND

[0003] Benzopinacol (i.e. 1,1,2,2-tetraphenyl-1,2-ethanediol) is a well-known free radical polymerization initiator. However, the use of benzopinacol in certain applications is limited by its very poor solubility in common organic solvents, particularly in applications where low volatile organic compounds (VOCs) are required.

[0004] Modifications of benzopinacol have been reported, for example in US 8,487,054, for example by reaction with chlorosilanes or polyorganosilane / siloxanes, by reaction with isocyanates, or by reaction with metal complexes and alcohols. It is said that reactivity and solubility can be improved by modification with chlorosilanes or polyorganosilane / siloxanes. However, solubility of those modified benzopinacols in organic solvents is not reported.

[0005] It would be desirable to provide a free radical polymerization initiator which can have the advantages of benzopinacol as a free radical polymerization initiator, but with increased solubility in organic solvents. SUMMARY

[0007] In one aspect, the present invention provides a copolymer comprising the following monomers in copolymerized form: (A) an allyloxy carboxyl substituted benzopinacol monomer of formula (I):

[0008]

[0009] and (B) at least one ethylenically unsaturated monomer.

[0010] In another aspect, the present invention provides the use of the copolymer described herein as a free radical polymerization initiator.

[0011] In another aspect, the present invention provides an allyloxy carboxyl substituted benzopinacol of formula (I).

[0012] The inventors have found that a copolymer comprising (A) an allyloxy carboxyl substituted benzopinacol monomer of formula (I) and (B) at least one ethylenically unsaturated monomer in copolymerized form is particularly useful as a free radical polymerization initiator, which has a much higher solubility compared to traditional small molecule benzopinacol initiators, and is therefore easier to handle during application processes. DETAILED DESCRIPTION

[0014] The present application will now be described in detail below. It is to be understood that the application can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs unless otherwise specifically defined.

[0015] In the context of the present application, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0016] In the context of the present application, the terms "comprising," "including," and the like are used in the sense of "including" and should be interpreted in the non-limiting, open-ended sense unless otherwise specifically indicated. That is, other components or elements can be present in addition to those specifically recited. The expression "consisting of or "consisting essentially of can be included within "comprising" or like expressions.

[0017] In the context of the present application, the terms "copolymer" and "copolymerization initiator" can also be used when referring to a copolymer comprising (A) an allyloxy carboxyl substituted benzoin monomer of formula (I) and (B) at least one olefinically unsaturated monomer.

[0018] In the context of the present application, the term "comonomer (A)" can also be used when referring to (A) an allyloxy carboxyl substituted benzoin monomer of formula (I).

[0019] In the context of the present application, the term "comonomer (B)" can also be used when referring to (B) at least one olefinically unsaturated monomer.

[0020] In the context of the present application, the term (meth)acrylate stands for acrylate and / or methacrylate.

[0021] The copolymerization initiator according to the present application comprises the following monomers in copolymerized form:

[0022] (A) an allyloxy carboxyl substituted benzoin monomer of formula (I):

[0023]

[0024] and

[0025] (B) at least one olefinically unsaturated monomer.

[0026] It is to be understood that the copolymerization initiator according to the present application is a copolymer comprising structural units resulting from comonomer (A) and structural units resulting from comonomer (B) by addition copolymerization.

[0027] In some embodiments, the copolymerization initiator according to the present application comprises comonomer (A) and comonomer (B) in random copolymerized form.

[0028] The olefinically unsaturated monomers as comonomers (B) are not particularly limited. Any compound comprising at least one olefinic double bond suitable for polymerization with the comonomers (A) can be used as comonomer (B). For example, the olefinically unsaturated monomers can be selected from the group consisting of a, b-unsaturated carboxylic acids and esters thereof, olefinically unsaturated nitriles, C1-C 20 vinyl esters of carboxylic acids, vinyl aromatics having up to 20 carbon atoms, vinyl halides, C1-C 20 vinyl ethers of alcohols, C2-C 20 unsaturated alkenes or any combination thereof.

[0029] In some embodiments, the comonomers (B) comprise at least one a, b-unsaturated carboxylic acid ester. Preferably, the at least one a, b-unsaturated carboxylic acid ester is selected from the group consisting of C1-C 20 alkyl esters of C3-C6-a, b-unsaturated carboxylic acids, C3-C 12 cycloalkyl esters of C3-C6-a, b-unsaturated carboxylic acids and any combination thereof. More preferably, the at least one a, b-unsaturated carboxylic acid ester is selected from the group consisting of (meth)acrylic acid C1-C 20 alkyl esters, (meth)acrylic acid C3-C 12 cycloalkyl esters and any combination thereof.

[0030] Thus, in some further embodiments, the copolymerization initiator according to the present application comprises:

[0031] (A) an allyloxy carboxyl substituted benzopinacol monomer of formula (I):

[0032]

[0033] and

[0034] (B) at least one olefinically unsaturated monomer selected from the group consisting of (meth)acrylic acid C1-C 20 alkyl esters, (meth)acrylic acid C3-C 12 cycloalkyl esters and any combination thereof, preferably (meth)acrylic acid C1-C 20 alkyl esters, more preferably (meth)acrylic acid C4-C 18 alkyl esters, in particular (meth)acrylic acid C4-C 12 alkyl esters.

[0035] (meth)acrylic acid C1-C 20Examples of alkyl esters can include, but are not limited to, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, t-butyl acrylate, t-butyl methacrylate, pentyl acrylate, pentyl methacrylate, hexyl acrylate, hexyl methacrylate, octyl acrylate such as 2-ethylhexyl acrylate, octyl methacrylate such as 2-ethylhexyl methacrylate, nonyl acrylate such as 3,3,5-trimethylhexyl acrylate, nonyl methacrylate such as 3,3,5-trimethylhexyl methacrylate, dodecyl acrylate such as lauryl acrylate, dodecyl methacrylate such as lauryl methacrylate, tridecyl acrylate, tridecyl methacrylate, tetradecyl acrylate, tetradecyl methacrylate, pentadecyl acrylate, pentadecyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate, heptadecyl acrylate, heptadecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, or any combination thereof.

[0036] C3-C12cycloalkyl (meth)acrylates 12 Examples of cycloalkyl esters can include, but are not limited to, cyclopentyl acrylate, cyclopentyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, methylcyclohexyl acrylate, methylcyclohexyl methacrylate, t-butylcyclohexyl acrylate, t-butylcyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, or any combination thereof.

[0037] In some embodiments, the copolymerization initiator according to the present application comprises:

[0038] (A) an allyloxy carboxyl substituted benzopinacol monomer of Formula (I):

[0039]

[0040] and

[0041] (B) at least one ethylenically unsaturated monomer selected from the group consisting of n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, t-butyl acrylate, t-butyl methacrylate, pentyl acrylate, pentyl methacrylate, hexyl acrylate, hexyl methacrylate, octyl acrylate such as 2-ethylhexyl acrylate, octyl methacrylate such as 2-ethylhexyl methacrylate, nonyl acrylate such as 3,3,5-trimethylhexyl acrylate, nonyl methacrylate such as 3,3,5-trimethylhexyl methacrylate, dodecyl acrylate such as lauryl acrylate, dodecyl methacrylate such as lauryl methacrylate, tridecyl acrylate, tridecyl methacrylate, tetradecyl acrylate, tetradecyl methacrylate, pentadecyl acrylate, pentadecyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate, heptadecyl acrylate, heptadecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, and any combination thereof.

[0042] In some other embodiments, the copolymerization initiator according to the present application comprises:

[0043] (A) an allyloxy carboxyl substituted benzopinacol monomer of Formula (I):

[0044]

[0045] and

[0046] (B) at least one ethylenically unsaturated monomer selected from the group consisting of n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, and any combination thereof.

[0047] In one particular embodiment, the copolymerization initiator according to the present application comprises:

[0048] (A) an allyloxy carboxyl substituted benzopinacol monomer of Formula (I):

[0049]

[0050] and

[0051] (B) at least one of n-butyl acrylate and n-butyl methacrylate, at least one of 2-ethylhexyl acrylate and 2-ethylhexyl methacrylate, and at least one of lauryl acrylate and lauryl methacrylate.

[0052] According to any of the embodiments described herein, in the copolymerization initiator according to the present application, the total structural units from the co-monomer (A) and the total structural units from the co-monomer (B) are contained in a weight ratio of 1 :30 to 1 :10, preferably 1 :25 to 1 :15, in particular 1 :20 to 1 :16.

[0053] The copolymerization initiator according to the present application can have a number average molecular weight (Mn) of 5,000 to 500,000 g / mol, preferably 10,000 to 200,000 g / mol, more preferably 20,000 to 100,000 g / mol, most preferably 30,000 to 70,000 g / mol, measured by gel permeation chromatography (GPC) in THF with polystyrene standards.

[0054] The copolymerization initiator according to the present application can have a number average molecular weight (Mn) of 5,000 to 500,000 g / mol, preferably 10,000 to 200,000 g / mol, more preferably 20,000 to 100,000 g / mol, most preferably 30,000 to 70,000 g / mol, measured by gel permeation chromatography (GPC) in THF with polystyrene standards.

[0055] The process for preparing the copolymerization initiator according to the present application is not particularly limited and can be carried out, for example, by radical polymerization, in particular thermal radical polymerization, of the co-monomer (A) and the co-monomer (B). Any conventional process conditions for radical polymerization such as solvent, polymerization temperature and polymerization initiator can be used for the purpose of the present application.

[0056] The present application also provides a novel compound, an allyloxy carboxyl substituted benzopinacol of formula (I):

[0057]

[0058] The compound of formula (I) can be prepared by subjecting allyl 4-benzoylbenzoate to a pinacol coupling reaction. Pinacol coupling reactions are well known in the art and can be carried out by various methods. For example, the pinacol coupling reaction can be carried out in the presence of a metal reducing agent such as Zn, Mg and Ni powder in aqueous ammonium chloride and optionally with an inert organic solvent such as THF.

[0059] The present application further provides the use of the above-mentioned copolymer as a radical polymerization initiator.

[0060] The copolymerization initiator can be used in various systems comprising one or more ethylenically unsaturated monomers such as (meth)acrylate and styrene functional monomers or comprising polymers containing ethylenically unsaturated functionality such as unsaturated polyesters. It will be appreciated that the copolymerization initiator can be used in any system comprising a conventional pinacol initiator such as benzopinacol.

[0061] The copolymerization initiator is particularly suitable for use in coatings, for example automotive coatings, comprising monomers having at least one ethylenic double bond and / or oligomeric reactive diluents.

[0062] Embodiments

[0063] Various embodiments are listed below. It will be appreciated that the embodiments listed below can be combined with all aspects and other embodiments in accordance with the scope of the present application.

[0064] Embodiment 1

[0065] A copolymer comprising the following monomers in copolymerized form:

[0066] (A) an allyloxy carboxyl substituted benzopinacol monomer of formula (I):

[0067]

[0068] and

[0069] (B) at least one ethylenically unsaturated monomer.

[0070] Embodiment 2

[0071] A copolymer according to embodiment 1 comprising a copolymer of (A) an allyloxy carboxyl substituted benzopinacol monomer of formula (I) and (B) at least one ethylenically unsaturated monomer in random copolymerized form.

[0072] Embodiment 3

[0073] A copolymer according to embodiment 1 or 2 wherein (B) the at least one ethylenically unsaturated monomer is selected from the group consisting of a, b-unsaturated carboxylic acids and esters thereof, ethylenically unsaturated nitriles, C1-C 20 vinyl esters of carboxylic acids, vinyl aromatics having up to 20 carbon atoms, vinyl halides, C1-C 20 vinyl ethers of alcohols, C2-C 20 unsaturated alkenes and any combination thereof.

[0074] Embodiment 4

[0075] A copolymer according to any one of embodiments 1 to 3 wherein (B) the at least one ethylenically unsaturated monomer comprises at least one a, b-unsaturated carboxylic acid ester, for example a C1-C20 Alkyl esters, C3-C6-α,β-unsaturated carboxylic acids 12 Cycloalkyl esters or any combination thereof, especially (meth)acrylic acid C1-C 20 Alkyl esters, (meth)acrylic acid C3-C 12 Cycloalkyl esters or any combination thereof.

[0076] Implementation Plan 5

[0077] According to any one of the embodiments 1-4, in the copolymer, (B) at least one olefinically unsaturated monomer is selected from (meth)acrylic acid C1-C 20 Alkyl esters, (meth)acrylic acid C3-C 12 Cycloalkyl esters and any combination thereof, preferably (meth)acrylic acid C1-C 20 Alkyl esters, more preferably (meth)acrylic acid C4-C 18 Alkyl esters, especially (meth)acrylic acid C4-C 12 Alkyl esters.

[0078] Implementation Plan 6

[0079] According to any one of the embodiments 1-5, in the copolymer, (B) at least one olefinically unsaturated monomer is selected from n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, pentyl acrylate, pentyl methacrylate, hexyl acrylate, hexyl methacrylate, octyl acrylate such as 2-ethylhexyl acrylate, octyl methacrylate such as 2-ethylhexyl methacrylate, nonyl acrylate such as 3,3,5-trimethylhexyl acrylate, nonyl methacrylate such as 3,3,5-trimethylhexyl methacrylate, dodecyl acrylate such as lauryl acrylate, dodecyl methacrylate such as lauryl methacrylate, tridecyl acrylate, tridecyl methacrylate, tetradecyl acrylate, tetradecyl methacrylate, pentadecyl acrylate, methyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate, heptadecanyl acrylate, heptadecanyl methacrylate, octadecyl acrylate, octadecyl methacrylate, and any combination thereof.

[0080] Implementation Plan 7

[0081] According to any one of the embodiments 1-6, the copolymer wherein (B) at least one olefinic unsaturated monomer is selected from n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate and any combination thereof.

[0082] Implementation Plan 8

[0083] The copolymer according to any one of embodiments 1 to 7, which comprises:

[0084] (A) allyloxy carboxyl substituted benzopinacol monomers of formula (I):

[0085]

[0086] and

[0087] (B) at least one of n-butyl acrylate and n-butyl methacrylate, at least one of 2- ethylhexyl acrylate and 2-ethylhexyl methacrylate and at least one of lauryl acrylate and lauryl methacrylate.

[0088] Embodiment 9

[0089] The copolymer according to any one of embodiments 1 to 8, wherein the total structural units from co-monomer (A) and the total structural units from co-monomer (B) are comprised in a weight ratio of 1 :30 to 1 :10, preferably 1 :25 to 1 :15, in particular 1 :20 to 1 :16.

[0090] Embodiment 10

[0091] The copolymer according to any one of embodiments 1 to 9, having a number average molecular weight (Mn) of 5,000 to 500,000 g / mol, preferably 10,000 to 200,000 g / mol, more preferably 20,000 to 100,000 g / mol, most preferably 30,000 to 80,000 g / mol.

[0092] Embodiment 11

[0093] The copolymer according to any one of embodiments 1 to 10, having a weight average molecular weight (Mn) of 20,000 to 1,000,000 g / mol, preferably 40,000 to 800,000 g / mol, more preferably 80,000 to 500,000 g / mol, most preferably 100,000 to 300,000 g / mol.

[0094] Embodiment 12

[0095] The copolymer according to any one of embodiments 1 to 11, which can be obtained or is obtained by free radical polymerization, in particular thermal free radical polymerization.

[0096] Embodiment 13

[0097] Use of the copolymer according to any one of embodiments 1 to 12 as free radical polymerization initiator.

[0098] Embodiment 14

[0099] Use according to embodiment 13, for a coating, such as an automotive coating, comprising a monomer and / or an oligomeric reactive diluent having at least one olefinic double bond.

[0100] Embodiment 15

[0101] Allyloxy carboxyl substituted benzopinacols of formula (I):

[0102] Example

[0103] The application will be further illustrated by examples, which are not intended to limit the scope of the application. Example 1: Synthesis of allyloxy carboxyl substituted benzopinacols of formula (I)

[0104] 1.1 Synthesis of 4-benzoylbenzoic acid allyl ester

[0105]

[0106] In a 100 mL round bottom flask, 49 mL of N,N-dimethylformamide (DMF), 4.87 g of 4-benzoylbenzoic acid (0.0215 moles), 4.3 g of potassium carbonate (0.0323 moles) and 3.9 g of allyl bromide (0.0323 moles) were added and then reacted at 65 °C for 5 hours under stirring. After purification by column chromatography with a mobile phase of 1.5% methyl tert-butyl ether in chloroform, 4-benzoylbenzoic acid allyl ester was obtained in a yield of 5.3 g.

[0107] 1.2 Coupling of 4-benzoylbenzoic acid allyl ester

[0108]

[0109] In a 1 L round bottom flask, 262 mL of tetrahydrofuran, 26.2 g of 4-benzoylbenzoic acid allyl ester (0.0983 moles), 19.28 g of zinc powder (0.295 moles) and 184 mL of 30% aqueous ammonium chloride were added and heated to reflux for 6 hours under stirring. After purification by column chromatography with a mobile phase of 1.5% methyl tert-butyl ether in chloroform, the compound of formula (I) was obtained in a yield of 3.28 g.

[0110] 1 H NMR (500 MHz, DMSO-d6, TMS): δH= 4.75-4.77 (t, 2H), 5.24-5.27 (dd, 1H), 5.36-5.40 (dd, 1H), 6.00 (m, 1H), 6.37 (s, 1H), 7.10-7.12 (t, 3H), 7.27-7.31 (m, 2H), 7.51-7.55 (t, 2H), 7.71-7.73 (m, 2H).1 H NMR spectra are shown in Figure 1

[0111] Example 2: Synthesis of the copolymerization initiator

[0112] Into a 100 mL three-necked flask equipped with a nitrogen inlet adapter, 10 g of the solvent naphtha 160 / 180 was added and heated to 80 °C. A solution of 0.5 g of the compound of formula (I), 3 g of 2-ethylhexyl acrylate, 3 g of n-butyl acrylate and 3 g of lauryl acrylate dissolved in 25 g of chloroform was dosed into the flask under stirring within 3.25 hours; simultaneously, a solution of 0.2 g of t-butyl peroxy-2-ethylhexanoate dissolved in 2 g of the solvent naphtha 160 / 180 was dosed into the flask within 3.5 hours. After the complete addition, the reaction system was kept under stirring at the same temperature for 1 hour and then cooled down to complete the polymerization. The whole process was carried out under nitrogen purge. A transparent viscous polymer solution was obtained. The conversion of the compound of formula (I) was 92% as determined by liquid chromatography.

[0113] The resulting polymer had a number average molecular weight (Mn) of 55,200 g / mol and a weight average molecular weight (Mw) of 218,000 g / mol and a PDI of 3.95 as measured by GPC in THF with polystyrene standards.

[0114] Example 3: Polymerization performance test

[0115] 3.1 Preparation of the polymerization system with copolymerization initiator

[0116] The transparent viscous polymer solution obtained from example 2 was vacuumed to remove part of the solvent to obtain a polymer solution with a solid content of 50% as measured according to GB 24409-2020. The obtained polymer solution was used as the copolymerization initiator system. The benzopinacol structural units accounted for 2.5 wt% of the total weight of the copolymerization initiator system. The solvent of the copolymerization initiator system consisted of 12.2 wt% chloroform and 87.8 wt% solvent naphtha as determined by gas chromatography.

[0117] A monomer solution was prepared by mixing 90 g of trimethylolpropane triacrylate (TMPTA) and 2 g of butyl glycol under stirring. 4 g of the copolymerization initiator system was added into the monomer solution and stirred at room temperature for 1 hour. The resulting mixture was a transparent and clear solution which would be used as the polymerization system.

[0118] 3.2 Preparation of the polymerization system with benzopinacol

[0119] ​A monomer solution was prepared by mixing 90 g of TMPTA, 2 g of butyl glycol, 0.24 g of chloroform and 1.76 g of solvent naphtha 160 / 180 under stirring. 1 g of pinanetriol was added to the monomer solution and stirred for 1 hour at room temperature. The resulting mixture was a transparent liquid with fine particles suspended, which was used as the polymerization system.

[0120] 3.3 Preparation of a polymerization system with pinanetriol

[0121] A monomer solution was prepared by mixing 90 g of TMPTA and 10 g of butyl glycol under stirring. 1 g of pinanetriol was added to the monomer solution and stirred for 1 hour at room temperature. The resulting mixture was a transparent liquid with fine particles suspended, which was used as the polymerization system.

[0122] 3.4 Preparation of a polymerization system with a compound of formula (I)

[0123] A monomer solution was prepared by mixing 90 g of TMPTA and 10 g of butyl glycol under stirring. 1 g of a compound of formula (I) was added to the monomer solution and stirred for 1 hour at room temperature. The resulting mixture was a transparent liquid with fine particles suspended, which was used as the polymerization system.

[0124] The polymerization systems were measured using a dynamic mechanical analyzer (HAAKE Viscotester iQ Air rheometer) to characterize the initiation performance of the initiators. The measurements were operated in OSC mode with a heating rate of 4.67 °C / min. The onset temperature was determined from the measurement curve as an indicator of the initiation performance. The test results are summarized in Table 1.

[0125] Table 1

[0126] Polymerization system Example 3.1 a) ]]> Example 3.2 b) ]]> Example 3.3 c) ]]> Example 3.4 d) ]] Starting temperature (°C) 118 134 118 121

[0127] a) Initiator: copolymer of the application; Solvent: 2 g of butyl glycol, 0.24 g of chloroform and 1.76 g of solvent naphtha 160 / 180

[0128] b) Initiator: pinanetriol; Solvent: 2 g of butyl glycol, 0.24 g of chloroform and 1.76 g of solvent naphtha 160 / 180

[0129] c) Initiator: pinanetriol; Solvent: 10 g of butyl glycol

[0130] d) Initiator: substituted pinanetriol of formula (I); Solvent: 10 g of butyl glycol

[0131] It can be seen that the polymerization system of Example 3.1 using the copolymerization initiator of the present application shows a much lower onset temperature than the polymerization system of Example 3.2 using benzopinacol under the same solvent composition. The onset temperature of the polymerization system using benzopinacol is lower at a much higher solvent amount, as shown by the comparison between the polymerization systems of Example 3.2 and Example 3.3. It is believed that the poor solubility of benzopinacol results in poor initiation efficiency, which is the reason for the higher onset temperature of the polymerization system of Example 3.2.

[0132] While benzopinacol can provide suitable initiation performance in a polymerization system containing sufficient amount of solvent, the large amount of solvent can result in undesirable VOC and can require a longer dissolution process and additional handling process such as filtration. In the case of allyloxy carboxyl substituted benzopinacol, the poor solubility of benzopinacol is not compensated, as can be seen from the test results of the polymerization system of Example 3.4, which shows even poorer initiation performance than benzopinacol. In contrast, the desired initiation performance has been achieved by the copolymerization initiator of the present application, while requiring a small amount of organic solvent and simplifying the process.

[0133] The application has been described with reference to particular embodiments. It is to be understood that the embodiments are merely illustrative of the principles and applications of the present application. Numerous modifications and adaptations will be readily apparent to those skilled in the art without departing from the spirit and scope of the present application. Therefore, the application is intended to cover all such modifications and variations as fall within the scope of the appended claims and equivalents thereof.

Claims

1. A copolymer comprising the following monomers in copolymerized form: (A) an allyloxy carboxyl substituted benzopinacol monomer of formula (I): ###0001### (I) and (B) at least one ethylenically unsaturated monomer.

2. The copolymer according to claim 1 comprising a copolymer of (A) an allyloxy carboxyl substituted benzopinacol monomer of formula (I) and (B) at least one ethylenically unsaturated monomer in random copolymerized form.

5. The copolymer according to any one of claims 1 to 4 wherein (B) the at least one ethylenically unsaturated monomer comprises at least one a, β-unsaturated carboxylate.

12. The copolymer according to any one of claims 1 to 4 wherein (B) the at least one ethylenically unsaturated monomer is selected from the group consisting of n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, t-butyl acrylate, t-butyl methacrylate, pentyl acrylate, pentyl methacrylate, hexyl acrylate, hexyl methacrylate, octyl acrylate, octyl methacrylate, nonyl acrylate, nonyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, tetradecyl acrylate, tetradecyl methacrylate, pentadecyl acrylate, pentadecyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate, heptadecyl acrylate, heptadecyl methacrylate, octadecyl acrylate, octadecyl methacrylate and any combination thereof.

3. The copolymer according to claim 1, wherein (B) at least one olefinically unsaturated monomer is selected from the group consisting of α,β-unsaturated carboxylic acids and esters thereof, olefinically unsaturated nitriles, vinyl esters of carboxylic acids having up to 20 carbon atoms, vinyl aromatics having up to 20 carbon atoms, vinyl halides, vinyl ethers of alcohols having up to 20 carbon atoms, C2-C20 alcohols having one or two olefinic double bonds, and any combinations thereof. 20 vinyl esters of carboxylic acids having up to 20 carbon atoms, vinyl aromatics having up to 20 carbon atoms, vinyl halides, vinyl ethers of alcohols having up to 20 carbon atoms, C2-C20 alcohols having one or two olefinic double bonds, and any combinations thereof. 20 vinyl esters of carboxylic acids having up to 20 carbon atoms, vinyl aromatics having up to 20 carbon atoms, vinyl halides, vinyl ethers of alcohols having up to 20 carbon atoms, C2-C20 alcohols having one or two olefinic double bonds, and any combinations thereof. 20 unsaturated alkenes and any combinations thereof.

4. The copolymer according to claim 2, wherein (B) at least one olefinically unsaturated monomer is selected from the group consisting of α,β-unsaturated carboxylic acids and esters thereof, olefinically unsaturated nitriles, vinyl esters of carboxylic acids having up to 20 carbon atoms, vinyl aromatics having up to 20 carbon atoms, vinyl halides, vinyl ethers of alcohols having up to 20 carbon atoms, C2-C20 alcohols having one or two olefinic double bonds, and any combinations thereof. 20 vinyl esters of carboxylic acids having up to 20 carbon atoms, vinyl aromatics having up to 20 carbon atoms, vinyl halides, vinyl ethers of alcohols having up to 20 carbon atoms, C2-C20 alcohols having one or two olefinic double bonds, and any combinations thereof. 20 vinyl esters of carboxylic acids having up to 20 carbon atoms, vinyl aromatics having up to 20 carbon atoms, vinyl halides, vinyl ethers of alcohols having up to 20 carbon atoms, C2-C20 alcohols having one or two olefinic double bonds, and any combinations thereof. 20 unsaturated alkenes and any combinations thereof.

13. The copolymer according to any one of claims 1 to 4 wherein (B) the at least one ethylenically unsaturated monomer is selected from the group consisting of 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 3,3,5-trimethylhexyl acrylate, 3,3,5-trimethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate and any combination thereof.

6. The copolymer according to any one of claims 1-4, wherein (B) at least one olefinically unsaturated monomer comprises the C1-C of a C3-C6-α,β-unsaturated carboxylic acid. 20 Alkyl esters, C3-C6-α,β-unsaturated carboxylic acids 12 Cycloalkyl esters or any combination thereof.

7. The copolymer according to any one of claims 1-4, wherein (B) at least one olefinically unsaturated monomer comprises (meth)acrylic acid C1-C 20 Alkyl esters, (meth)acrylic acid C3-C 12 Cycloalkyl esters or any combination thereof.

8. The copolymer according to any one of claims 1-4, wherein (B) at least one olefinically unsaturated monomer is selected from (meth)acrylic acid C1-C. 20 Alkyl esters, (meth)acrylic acid C3-C 12 Cycloalkyl esters and any combination thereof.

9. The copolymer according to any one of claims 1 to 4, wherein (B) at least one olefinically unsaturated monomer is selected from the group consisting of C1-C12 (meth)acrylic acid alkyl esters. 20 alkyl esters.

10. The copolymer according to any one of claims 1 to 4, wherein (B) at least one olefinically unsaturated monomer is selected from the group consisting of C4-Ci8 (meth)acrylic acid alkyl esters. 18 alkyl esters.

11. The copolymer according to any one of claims 1 to 4, wherein (B) at least one olefinically unsaturated monomer is selected from the group consisting of C4-Ci8 (meth)acrylic acid alkyl esters. 12 alkyl esters.

14. The copolymer according to any one of claims 1 to 4 wherein (B) the at least one ethylenically unsaturated monomer is selected from the group consisting of n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate and any combination thereof.

15. The copolymer according to any one of claims 1 to 4 comprising: (A) an allyloxy carboxyl substituted benzopinacol monomer of formula (I): ###0001### (I) and (B) at least one of n-butyl acrylate and n-butyl methacrylate, at least one of 2-ethylhexyl acrylate and 2-ethylhexyl methacrylate and at least one of lauryl acrylate and lauryl methacrylate.

16. The copolymer according to any one of claims 1 to 4 wherein the total structural units from copolymerized monomer (A) and the total structural units from copolymerized monomer (B) are comprised in a weight ratio of 1 :30 to 1 :

10.

17. The copolymer according to any one of claims 1 to 4 wherein the total structural units from copolymerized monomer (A) and the total structural units from copolymerized monomer (B) are comprised in a weight ratio of 1 :25 to 1 :

15. ​ ​ ​ ​ 18. The copolymer according to any one of claims 1 to 4, wherein the total structural units from comonomer (A) and the total structural units from comonomer (B) are comprised in a weight ratio of 1 :20 to 1 :

16.

19. The copolymer according to claim 15, wherein the total structural units from comonomer (A) and the total structural units from comonomer (B) are comprised in a weight ratio of 1 :30 to 1 :

10.

20. The copolymer according to claim 15, wherein the total structural units from comonomer (A) and the total structural units from comonomer (B) are comprised in a weight ratio of 1 :25 to 1 :

15.

21. The copolymer according to claim 15, wherein the total structural units from comonomer (A) and the total structural units from comonomer (B) are comprised in a weight ratio of 1 :20 to 1 :

16.

22. The copolymer according to any one of claims 1 to 4, having a number average molecular weight (Mn) of 5,000 to 500,000 g / mol.

23. The copolymer according to any one of claims 1 to 4, having a number average molecular weight (Mn) of 10,000 to 200,000 g / mol.

24. The copolymer according to any one of claims 1 to 4, having a number average molecular weight (Mn) of 20,000 to 100,000 g / mol.

25. The copolymer according to any one of claims 1 to 4, having a number average molecular weight (Mn) of 30,000 to 80,000 g / mol.

26. The copolymer according to any one of claims 1 to 4, having a weight average molecular weight (Mn) of 20,000 to 1,000,000 g / mol.

27. The copolymer according to any one of claims 1 to 4, having a weight average molecular weight (Mn) of 40,000 to 800,000 g / mol.

28. The copolymer according to any one of claims 1 to 4, having a weight average molecular weight (Mn) of 80,000 to 500,000 g / mol.

29. The copolymer according to any one of claims 1 to 4, having a weight average molecular weight (Mn) of 100,000 to 300,000 g / mol.

30. The copolymer according to any one of claims 1 to 4, obtained by free radical polymerization.

31. The copolymer according to any one of claims 1 to 4, obtained by thermal free radical polymerization.

32. The copolymer according to claim 29, obtained by free radical polymerization.

33. The copolymer according to claim 29, obtained by thermal free radical polymerization.

34. Use of the copolymer according to any one of claims 1 to 33 as free radical polymerization initiator.

35. The use according to claim 34 for a coating, comprising a monomer having at least one olefinic double bond and / or an oligomeric reactive diluent.

36. The use according to claim 34 for an automotive coating, comprising a monomer having at least one olefinic double bond and / or an oligomeric reactive diluent.

37. An allyloxy carboxyl substituted benzopinacol of formula (I)

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