Abstract:
A polymerizable or copolymerizable unsaturated polyester composition contains a peroxide initiator and a compound of the formula: ##STR1## wherein Y is hydroxy, alkoxy having 1-12 carbon atoms, or alkyl having 1-12 carbon atoms, and Z is hydrogen, hydroxycarbonyl, alkyl, cycloalkyl, aralkyloxycarbonyl having 1-20 carbon atoms, benzoyl, or alkanoyl having 1-4 carbon atoms.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a process for the preparation of a polymerizable or copolymerizable composition consisting of a polymerizable unsaturated polyester or a mixture of such an ester and a monomer copolymerizable therewith and a peroxide initiator, and to the polymerization or copolymerization of like mixtures and to articles entirely or substantially composed of (co)polymerisates obtained by (co)polymerization of the compositions according to the invention. 
     Unsaturated polyesters may be obtained by reaction of approximately equivalent amounts of a polyvalent alcohol such as ethylene glycol, diethylene glycol, triethylene glycol, trimethylene glycol, propylene glycol, pentaerythritol and other diols or polyols with an unsaturated dibasic carboxylic acid or carboxylic anhydride such as maleic acid, maleic anhydride, fumaric acid, itaconic acid or citraconic acid. These unsaturated dibasic carboxylic acids or anhydrides are often used in combination with aromatic and/or saturated aliphatic dicarboxylic acids or the anhydrides derived therefrom, such as phthalic acid, phthalic anhydride, isophthalic acid, tetrachlorophthalic acid, malonic acid, adipic acid, sebacic acid, tartaric acid, etc. 
     Unsaturated polyesters containing vinyl group or vinylidene groups may be obtained by polycondensation of α,β-unsaturated mono carboxylic acids such as acrylic or methacrylic acid, with mono-, di- or polyhydric alcohols. As examples of these alcohols may be mentioned: methanol, ethanol, isopropanol, cyclohexanol, phenol, ethylene glycol, propylene glycol, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxycyclohexyl)propane, 2,2-bis(4-β-hydroxyethyloxyphenyl)-propane, pentaerythritol and dimers thereof, trimethol propane and glycerol, and the complex diols or polyols as described in the Netherlands Patent Application No. 6 808 040, the German Patent Application DAS No. 1 645 379, the U.S. Pat. Nos. 2,895,950 and 2,628,178, the British Pat. Nos. 928,307 and 965,826 and the French Pat. No. 1 404 000. 
     Unsaturated polyester containing vinyl groups or vinylidene groups also may be obtained by reacting α,β-unsaturated monocarboxylic acids with compounds containing epoxy groups, such as bisphenol A bis (glycidyl ether). 
     The unsaturated polyesters required to this end may be dissolved in monomers copolymerizable with the polyester, which contain one or more CH 2  ═C&lt; groups such as styrene, vinyl toluene, methylmethacrylate, ethyleneglycolmethacrylate, etc. 
     The solutions that are used most are those that contain 70-50% by weight of unsaturated polyester and 30-50% by weight of copolymerizable monomer. Preference is given to styrene as copolymerizable monomer. 
     In order to improve the stability of the unsaturated polyesters, inhibitors are incorporated in them in amounts ranging from 0.001 to 0.03% by weight. The most commonly used inhibitors are hydroquinone, quinone and paratert.butyl catechol. 
     The above-described unsaturated polyester or mixtures thereof with copolymerizable monomers can be (co)polymerized under the influence of hydrogen peroxide and organic hydroperoxides, ketone peroxides and diacyl peroxides, that generate free radicals. 
     If this (co)polymerization is to be carried out at room temperature or at a slightly elevated temperature use should be made of combinations of the afore-mentioned peroxides and accelerators, such as organic metal compounds or a tertiary amine. 
     DESCRIPTION OF THE INVENTION 
     It has now been found that the peroxidic polymerization of an unsaturated polyester or the copolymerization of such an ester with a suitable monomer can be accelerated considerably if in addition to the peroxide initiator there is incorporated in the polyester or the polyester-monomer mixture a compound having the general formula: ##STR2## where Y is a hydroxy group, an alkoxy group or an alkyl group, having 1-12 C-atoms and Z represents hydrogen, a hydroxycarbonyl group, an alkyl group, cycloalkyl group, or aralkyloxy carbonyl group with 1-20 C-atoms, a benzoyl group, or an alkanoyl group, having 1-4 C-atoms, and the resulting composition is subsequently heated to the desired polymerization temperature. 
     As examples of compounds that may be used according to the invention may be mentioned: 
     floroglucinol; mono- and dialkyl ethers of floroglucinol, such as floroglucinol monomethyl ether, floroglucinol dimethyl ether, floroglucinolmonolauryl ether; 3,5-dihydroxy alkyl benzenes, such as 3,5-dihydroxy toluene, 3,5-dihydroxyisopropyl benzene; 2,4,6-trihydroxy benzoic acid; 2,4,6-trihydroxy(cyclo)alkyl benzoates such as 2,4,6-trihydroxy methyl benzoate, lauryl 2,4,6-trihydroxy benzoate, 4-t.butylcyclohexyl-2,4,6-trihydroxy benzoate, benzyl-2,4,6-trihydroxy benzoate; 2,4,6-trihydroxy phenyl ketones, such as 2,4,6-trihydroxy-acetophenone, 2,4,6-trihydroxybutyrophenone and 2,4,6-trihydroxybenzophenone. 
     The compounds according to the invention can be used in amounts ranging from 0.01 to 5.0% by weight, and preferably from 0.05 to 2.0% by weight, calculated on the polymer to be polymerized or the polymer monomer mixture to be copolymerized. 
     As initiators for the polymerization or copolymerization may be used hydrogen peroxide; ketone peroxides, such as acetylacetone peroxide, methylethylketone peroxide, cyclohexanone peroxide and methylisobutylketone peroxide; diacyl peroxide, such as benzoyl peroxide; peresters, such as tert.-butyl peroxide-2-ethyl hexanoate; perketals, such as 1,1-ditert.-butylperoxy-3,3,5-trimethyl cyclohexane and dialkyl peroxides, such as 1,3-bis(tert.-butylperoxyisopropyl)benzene. 
     If the (co)polymerization is to be carried out at room temperature or at slightly elevated temperature, tertiary amines, such as N,N-diethyl aniline, N,N-dimethyl toluidine or N,N-diethyl aniline or metal compounds are to be used as an accelerator. As metal compounds may be used organic cobalt, iron, copper, vanadium, cerium, manganese, tin, silver and mercury compounds and preferably cobalt naphthenate and cobalt octoate. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention will be further illustrated in the following examples. In these examples the gel time was determined by introducing mixtures in a test tube which was placed in a thermostatted bath of 20° C. and measuring the time elapsed between the preparation of these mixtures and their gelling moment. The curing at room temperature was measured with the aid of a Persoz hardness tester on unsaturated-polyester sheets having a thickness of 1 mm. During curing these sheets were covered with tin foil to prevent evaporation of the monomer, if present, and/or to prevent inhibition of atmospheric oxygen. 
     The (co)polymerization at elevated temperature was followed by placing a thermocouple in a sample present in a thermostatted bath of the desired temperature and recording the change of temperature with time. From the temperature-time curve thus obtained the minimum cure time and the time to peak exotherm were determined. 
     By minimum cure time is to be understood the time needed for the sample to reach a particular hardness; by peak exotherm is to be understood the highest temperature reached. 
     The test were carried out on the following samples: 
     Sample A: 
     the reaction product of 1.0 mole of maleic anhydride, 1.0 mole of phthalic anhydride, 1.1 moles of ethylene glycol and 1.1 moles of propane-1,2-diol made up with styrene to a styrene content of 35%. 
     Sample B: 
     the reaction product of 2 moles of bisphenol A bis (glycidyl ether) and 2 moles of methylmethacrylate made up with styrene to a styrene content of 45%. 
    
    
     EXAMPLE I 
     To 100 parts by weight of Sample A were added 0.5 parts by weight of a solution of cobalt naphthenate in dimethylphthalate containing 1% by weight of cobalt, 1 part by weight of hydrogen peroxide with an active O-content of 4% and 0.08 parts by weight of floroglucinol. Of the resulting composition the gel time at 20° C. and the Persoz hardness after 2, 6 and 24 hours were determined. The same measurements were done on a composition which did not contain floroglucinol and on compositions containing different amounts of accelerator. 
     The various compositions used and the gel times and hardness values measured are given in the following table. 
     
                                           TABLE I__________________________________________________________________________Sample A  100     100 100 100 100 100 100 100 100 100__________________________________________________________________________Cobaltaccelerator  1  0.5 0.5 0.5 1   1   1   2   2   2Hydrogenperoxide  1  1   1   1   1   1   1   1   1   1Floroglucinol  -- 0.08         0.16             0.32                 0.08                     0.16                         0.32                             0.08                                 0.16                                     0.32Geltime at20° C. in min  6  8   6   4.6 5.0 4.0 3.3 2.4 2.4 1.8Persoz hard-nessafter 2 hours  -- 64  90  108 85  101 141 81  108 145after 6 hours  26 103 122 139 115 138 160 111 136 164after 24 hours  71 149 160 175 154 171 189 151 171 194__________________________________________________________________________ 
    
     EXAMPLE II 
     To 100 parts by weight of sample A were added 1 part by weight of the cobalt accelerator described in Example I, 1 part by weight of hydrogen peroxide with an active O-content of 4% and 0.35 parts by weight of floroglucinol monomethyl ether. Of the resulting composition the gel time at 20° C. and the Persoz hardness after 2, 4 and 24 hours were determined. 
     The same measurements were carried out on composition which contained no compounds according to the invention or other compounds according to the invention. 
     The various compositions prepared and the gel times and hardness values measured are given in the following table. 
     
                                           TABLE II__________________________________________________________________________Sample A        100              100                 100                    100                       100                          100                             100                                100                                   100                                      100                                         100                                            100                                               100                                                  100__________________________________________________________________________Cobalt accelerator           1   1  1  1  1  1  1  1  1  1  1  1  1  1Hydrogen peroxide           1   1  1  1  1  1  1  1  1  1  1  1  1  1Floroglucinol monomethyl ether           -- 0.35                 -- -- -- -- -- -- -- -- -- -- -- --Floroglucinol dimethyl ether           -- -- 0.39                    -- -- -- -- -- -- -- -- -- -- --Floroglucinol monolauryl ether           -- -- -- 0.74                       -- -- -- -- -- -- -- -- -- --3,5-dihydroxytoluene           -- -- -- -- 0.31                          -- -- -- -- -- -- -- -- --2,4,6-trihydroxy benzoic           -- -- -- -- -- 0.43                             -- -- -- -- -- -- -- --acid2,4,6-trihydroxy methyl           -- -- -- -- -- -- 0.46                                -- -- -- -- -- -- --benzoateLauryl-2,4,6-trihydroxy-           -- -- -- -- -- -- -- 0.85                                   -- -- -- -- -- --benzoate4-t.-butylcyclohexyl-2,4,6-           -- -- -- -- -- -- -- -- 0.77                                      -- -- -- -- --trihydroxybenzoateBenzyl-2,4,6-trihydroxy-           -- -- -- -- -- -- -- -- -- 0.65                                         -- -- -- --benzoate2,4,6-trihydroxy-           -- -- -- -- -- -- -- -- -- -- 0.42                                            -- -- --acetophenone2,4,6-trihydroxy           -- -- -- -- -- -- -- -- -- -- -- 0.58                                               -- --benzophenone2,4,6-trihydroxy           -- -- -- -- -- -- -- -- -- -- -- -- 0.49                                                  --butyrophenone3,5-dihydroxyisopropyl           -- -- -- -- -- -- -- -- -- -- -- -- -- 0.38benzeneGel time at 20° C. (in min)           6   4  4  3  6  1  5  4  5  3  4  4  5  7Persoz hardnessafter 2 hours   -- 141                 118                    150                       103                          130                             26 38 30  70                                          80                                             89                                                64                                                   96after 6 hours   26 161                 144                    172                       147                          150                             55 65 61 120                                         111                                            117                                               105                                                  132after 24 hours  71 196                 184                    203                       188                          181                             107                                130                                   123                                      174                                         155                                            158                                               160                                                  170__________________________________________________________________________ 
    
     EXAMPLE III 
     To 100 parts by weight of Sample A were added 1 part by weight of the cobalt accelerator described in Example I, 1 part by weight of acetylacetone peroxide and 0.08 parts by weight of floroglucinol. Of the resulting composition the gel time at 20° C. and the Persoz hardness after 2, 6 and 24 hours were determined. 
     The same measurements were done on compositions not containing floroglucinol or containing floroglucinol in a different amount. The same measurements were also carried out on compositions containing a peroxide other than acetylacetone peroxide. 
     The compositions prepared and the measured gel times and hardness values are listed in the following table. 
     
                                           TABLE III__________________________________________________________________________Sample A      100            100               100                  100                     100                        100                           100                              100                                 100                                    100                                       100                                          100__________________________________________________________________________Cobalt accelerator          1  1  1  1  1  1  1  1  1  1  1  1Acetyl acetone peroxide         1  1  1  -- -- -- -- -- -- -- -- --(4.0% AO)Methylethyl ketone         -- -- -- 1  1  1  -- -- -- -- -- --peroxide (9.0% AO)Cyclohexane peroxide (6.5%         -- -- -- -- -- -- 1  1  1  -- -- --AO)Methylisobutyl ketone         -- -- -- -- -- -- -- -- -- 1  1  1peroxide (10.2% AO)Floroglucinol -- 0.08               0.32                  -- 0.08                        0.32                           -- 0.08                                 0.32                                    -- 0.08                                          0.32Gel time (in min) 20° C.          15             9  8 15  7  6 54  27                                  17                                     47                                        11                                           7Persoz hardnessafter 2 hours  73            100               122                  33  68                        101                           27  48                                  65                                    --  45                                           68after 6 hours 127            149               168                  80 115                        132                           68 106                                 112                                     59                                       109                                          125after 24 hours         169            178               210                  136                     167                        182                           132                              162                                 171                                    135                                       163                                          177__________________________________________________________________________ 
    
     EXAMPLE IV 
     To 100 parts by weight of sample B were added 1 part by weight of the accelerator described in Example I, 1 part by weight of acetylacetone peroxide and 0.8 parts by weight of floroglucinol. Subsequently, the gel time at 20° C. and the Persoz hardness after 2, 4 and 24 hours were determined. The same measurements were carried out on compositions which contained no floroglucinol or 0.32 parts by weight of floroglucinol and/or other peroxides. 
     The resulting compositions and the measured gel times and the hardness values are shown in the following table. 
     
                                           TABLE IV__________________________________________________________________________Sample B  100        100           100              100                 100                    100                       100                          100                             100                                100                                   100                                      100__________________________________________________________________________Cobalt accelerator      1  1  1  1  1  1 1   1  1  1  1  1Acetyl acetoneperoxide (4.0% AO)     1  1  1  -- -- -- -- -- -- -- -- --Methylethyl ketoneperoxide (9.0% AO)     -- -- -- 1  1  1  -- -- -- -- -- --Cyclohexanoneperoxide (5.5% AO)     -- -- -- -- -- -- 1  1  1  -- -- --Methylisobutylketone peroxide(10.2% AO)     -- -- -- -- -- -- -- -- -- 1  1  1Floroglucinol     -- 0.08           0.32              -- 0.08                    0.32                       -- 0.08                             0.32                                -- 0.08                                      0.32Gel time (in min)     1440         32            8 180                  20                     9 --  11                              8 119                                    19                                       10Persoz hardnessafter 2 hours     -- 128           203              -- 111                    202                       -- 151                             203                                -- 126                                      179  6 hours -- 203           251               20                 197                    258                       -- 210                             255                                 55                                   204                                      239  24 hours     -- 269           298              205                 270                    284                       -- 266                             284                                198                                   271                                      294__________________________________________________________________________ 
    
     EXAMPLE V 
     To 100 parts by weight of sample A were added 2 parts by weight of a benzoyl peroxide paste composed of 50% by weight of benzoyl peroxide and 50% by weight of softener and 0.08 parts by weight of floroglucinol. Subsequently, at a temperature of 70° C., the gel time, the minimum cure time, the time to peak exotherm, and the peak exotherm were determined. The same measurements were carried out on compositions which are listed in the following table. 
     
                                           TABLE V__________________________________________________________________________Sample A   100         100            100               100                  100                     100                        100                           100                              100                                 100                                    100                                       100__________________________________________________________________________Benzoyl peroxidepaste (50% -)      2  2  2  -- -- -- -- -- -- -- -- --Tert. butyl-per-2-ethylexanoate      -- -- -- 1  1  1  -- -- -- -- -- --1,1-di-tert-butyl-peroxy-3,3,5-trimethylcyclohexane(50% -)    -- -- -- -- -- -- 2  2  2  -- -- --1,3-bis (tert. butylperoxy-isopropyl)benzene    -- -- -- -- -- -- -- -- -- 1  1  1Floroglucinol      -- 0.08            0.32               -- 0.08                     0.32                        -- 0.08                              0.32                                 -- 0.08                                       0.32Bath temperature(°C.)      70 70 70 70 70 70 70 70 70 100                                    100                                       100Gel time (min)      12.7         5.8            5.8               12.8                  6.7                     6.3                        19.9                           10.9                              12.9                                 17.4                                    4.6                                       3.5Minimum curetime (min) 13.5         8.9            9.8               15.5                  9.5                     9.5                        24.4                           15.4                              19.6                                 19.7                                    7.1                                       6.9Time to peakexotherm (min)      18.9         12.3            13.3               18.7                  12.7                     12.3                        27.1                           18.4                              22.4                                 21.6                                    9.9                                       9.6Peak exotherm(°C.)      227         223            211               229                  229                     221                        223                           220                              212                                 238                                    261                                       248__________________________________________________________________________ 
    
     EXAMPLE VI 
     Of compositions listed in Table VI the gel time, the minimum cure time, the time to peak exotherm and the peak exotherm were determined in the way described in Example V. The results obtained are also included in this table. 
     
                                           TABLE VI__________________________________________________________________________Sample B   100         100            100               100                  100                     100                        100                           100                              100                                 100                                    100                                       100__________________________________________________________________________Benzoyl peroxidepaste (50% -)      2  2  2  -- -- -- -- -- -- -- -- --Tert. butylper-2-ethyl hexanoate      -- -- -- 1  1  1  -- -- -- -- -- --1,1-ditert-butyl-peroxy-3,3,5-tri-methylcyclohexane(50% -)    -- -- -- -- -- -- 2  2  2  -- -- --1,3-bis (tert. bu-tylperoxy-isopropyl)benzene    -- -- -- -- -- -- -- -- -- 1  1  1Floroglucinol      -- 0.08            0.32               -- 0.08                     0.32                        -- 0.08                              0.32                                 -- 0.08                                       0.32Bath temperature(°C.)      80 80 80 80 80 80 90 90 90 110                                    110                                       110Gel time (min)      13.5         6.5            -- 20.6                  14.8                     10.1                        28.2                           17.5                              12.0                                 17.7                                    7.7                                       6.6Minimum curetime (min) 16.9         9.8            -- 22.9                  17.2                     13.1                        30.6                           20.2                              16.0                                 21.2                                    10.6                                       9.0Time to peakexotherm (min)      19.6         12.7            12.0               26.1                  20.4                     16.1                        34.0                           23.5                              19.4                                 23.5                                    13.2                                       11.4Peak exotherm(°C.)      202         199            83 211                  214                     198                        228                           221                              217                                 251                                    253                                       252__________________________________________________________________________ 
    
     The invention is not limited to the afore-described examples, the scope of the invention allowing of many variants. 
     The cured unsaturated polyester/monomer mixture thus obtained can be used e.g. for the manufacture of casings for refrigerators, automobile parts, articles for the electronic industry, glass reinforced pipes, drains, tanks and the like.