FR2475562A1 - Reducing monomer volatility of unsatd. polyester resins - by addn. of a reaction prod. of an epoxy cpd. with a mono:carboxylic acid - Google Patents

Abstract

Resin compsn. with reduced monomer volatility, is comprised of a soln. of an unsatd. oligoester or polyester in a copolymerisable monomer, together with the usual inhibitors, fillers, catalysts, paraffins and other additives. The compsn. also contains 0.005-5 wt.% (w.r.t. resin) of >=1 monomer volatility-reducing agents RCOOCH2CH(OH)CH2O nA (I). In (I) R is pref. unbranched 12-22C alkadienyl, (hydroxy)alkyl or (hydroxh)alkenyl gp.; A is a phenyl gp.; opt. substd. on the 2 and/or 4 positions by 1 or 2 CH3 or Cl gps., or a gp. A(C=O)- where n = 1, or a p- or m-phenylene gp., a o-, m- or p- -C(=O)-C6H4-C(=O)- gp..gps. (I) or (II) (in which m=0-4) where n=2, or a gp. (in which X is H or -C(CH3)3, and k=0-6) where n = 2-8. The additives dissolve completely in the resin compsn. and do not settle on storage. They do not affect the viscosity, curing characteristics, storage properties or other technical properties of the resin. The additives greatly reduce loss of monomer by evapn. from still uncured resin layers after application e.g. as coatings, castings, or laminates. Unlike known paraffin or wax additives, the additives do not reduce the adhesion of subsequently-applied layers of the resin.

Description

 The present invention relates to a process for the production of unsaturated polyester resins used in the manufacture of laminates, molding compounds, varnish coatings and moldings.

 A process for the production of unsaturated polyester resins is known from the dissolution of unsaturated polyesters in monomers with the possible addition of innibitors, fillers and polymerization initiators. The monomers employed for the production of the polyester resins are volatile and partially evaporate during processing prior to curing the resin, including thin-coat coatings and large-area thin laminates.

 In order to prevent the evaporation of the volatile monomers, additives of the paraffin, wax, ceresin and emulsifier type, such as "water in lthu-lel" and "oil in water" emulsions, are introduced into the polyester resins and varnishes. British Patent Specification Nos. 713332 and 774807, as well as French Patent Specification No. 1061133, are known to be used as additives preventing the evaporation of the monomers used for the production of resins and resins. polyester varnishes, small amounts of paraffin wax or wax which are deposited on the surface during the curing of the resin and protect against the access of oxygen, while at the same time reducing the evaporation of the volatile monomers. These additives nonetheless form a separating layer, weakening the adhesion of subsequent layers of the laminate or varnish coating to the previously gelled or hardened carrier.

 Another known method of the description of the German Patent No. 2554930 recommends as additives - resins and molding compounds - waxes, sorbitol derivatives, glycerine, polycxyethylene, trimethylpropane, pentaerythritol butanotriol, pentose, hexose and other polyvalent alcohols, generally referred to as "water-in-oil" or "oil-in-water" emulsifiers - and not waxes. Their solubility in the polyester resin is limited and many of them cause turbidity of the resin after curing.

ou un groupe de formule générale 2,

dans laquelle m est de O à 4, n étant égal à 2, ou un groupe de formule générale 3,

dans laquelle X désigne l'atome d'hydrogène, ou un groupe -C(CH3)3 avec k s'élevant de O à 6 et n1 étant respectivement de 2 à 8.However, it has been unexpectedly found that unsaturated polyvalent resins with reduced evaporation of the monomer can be obtained by dissolving the unsaturated polyester in the monomer and introducing them into 100 parts by weight of polyester resin thus obtained. 0.005 to 5 parts by weight. (-spare or in mixture) of compounds having the general formula [RCOOH 2 CH / OH / CH 2 O-] nA, in which R denotes an alkyl, alkenyl, alkadienyl, hydroxyl, hydroxyalkyl or hydroxyalkenyl group, containing 12 to 22 carbon atoms, in particular unbranched, wherein A denotes a phenyl group, a phenyl group substituted in the 2-position and / or 4 by one or two CH 3 groups or by chlorine atoms, or a group of the general formula
AC (=) O- wherein n is 1, or p-phenyl, m-phenyl, or o-, m-, or p- (C) -O6H4-C-, or a group of formula 1

or a group of general formula 2,

in which m is from 0 to 4, where n is 2, or a group of general formula 3,

wherein X is hydrogen, or -C (CH3) 3 with k ranging from 0 to 6 and n1 being 2 to 8, respectively.

 A variant of the compounds proposed above may consist of the compounds of general formula identical and having the same meaning of R, when A denotes a linear or branched alkyl, alkenyl or alkylcarbonyl group, containing 2 to 8 carbon atoms or a group of general formula -OC- (CH 2) 1 -CO-, wherein 1 is 2 to 8, or a group of general formula -A 1 [-O-CH 2 -CH (CH 2 Cl) -] r, wherein A1 is an alkylene group containing 2 to 6 carbon atoms, or a group of the general formula -A2-O-A2-, or a group -A2-O-A2-O-A2, wherein A2 is a linear alkylene group or branched, containing 2 to 4 carbon atoms, especially a group -CH 2 CH 2 - or -CH 2 -CH (CH 3) -, wherein r is 0 to 3, not being 2.

 The compounds of the general formula DRCOOCH 2 CH (OH) CH 2 OX nA employed in the process according to the invention are most advantageously obtained by heating epoxy compounds with monocarboxylic acids. As catalysts, it is possible to use compounds of basic character, especially tertiary amines.

dans laquelle A et n ont la signification mentionnée plus haut, p.ex. l'éther phénylglycidylique, les résines diéniques de poids moléculaire moyen s'élevant numériquement de 400 à 1000, l'hexahydrophtaîate diglycidilique ou les résines époxy-vernis, l'éther allylglycidylique, les résines époxydes aliphatiques de poids moléculaire moyen s'élevant numériquement de 300 à 600, le sébaçate diglycidylique ou les résines d'oligomères d'épichlorohydrine.As the starting epoxide compounds, compounds of the general formula 4 are used,

in which A and n have the meaning mentioned above, eg phenylglycidyl ether, dienic resins having a number average molecular weight of 400 to 1000, diglycidyl hexahydrophthalate or epoxy-lacquered resins, allylglycidyl ether, aliphatic epoxy resins of average molecular weight ranging from 300 to 600 numerically, diglycidyl sebacate or epichlorohydrin oligomer resins.

 Starting monocarboxylic acids are those acids of the general formula RCOOH, wherein R has the meaning mentioned above, e.g. ex. stearic, palmitic, behenic, linoleic, ricinoleic or ricinenic acid.

 The compounds mentioned are soluble in the polyester resin, do not cause turbidity of the resin after curing and do not form a layer of separation between the layers executed separately from the molding, the coating or the laminate, while the polyester resins added with these compounds are characterized by the perfect adhesion of the successive layers of the molding, the coating or the polyester-glass laminate to the gelled or hardened front support.

 The composition of the polyester resins according to the invention comprises crosslinking monomers and acrylic or methacrylic oligo-esters, or maleic or fumaric polyesters, optionally modified in the known manner by phthalic acid, tetrachlorophthalic acid, tetrabromophthalic acid, isophthalic acid, terephthalic acid or adipic acid. sebacic acid and diene adducts of maleic anhydride with butadiene, hexadiene, anthracene, s-naphtholene, terpenes, cyclopentadiene, hexachlorocyclopentadiene, rosin rosin acids or by other acidic acids and anhydrides.

 The composition of the known maleic or fumaric polyesters comprises the following glycols: ethylenic, diethylenic, polyethylenic, 1,2-propylenic, dipropylenic, polypropylenic, 1,3-butyl, 1,6-hexylenic, neopentyl, propoxylenic and ethoxylated diene, 1, 2-cyclo hexaXiodiol with optional addition of mono- and polyfunctional alcohols, such as glycerine, trimethylolpropanes, hexano-olefins and the like.

dans laquelle R désigne un atome d'hydrogène ou un groupe méthacrylique, la valeur de m étant de O à 4, ou d'autres produits d'addition de l'acide acrylique ou méthacrylique aux résines époxydes.As acrylic and methacrylic acid oligomers, compounds of the general formula 5 are employed.

wherein R denotes a hydrogen atom or a methacrylic group, the value of m being from 0 to 4, or other adducts of acrylic or methacrylic acid to epoxy resins.

 As crosslinking monomers styrene, methyl methacrylate, vinyl acetate and acrylic oligo-esters are used, separately or in admixture.

 In order to stabilize the solutions of the oligo-esters or polyesters in the cross-linking monomers, hydroquinone, methylhydroquinone, quinones, picrinic acid and other compounds are added.

 As fillers of the polyester resins, glass fibers, chalk, kaolin, quartz flour, asbestos, silica, magnesium oxide and other known fillers are used.

 The polyester resins are cured at room temperature or higher by free radical initiators: benzoyl peroxide, methyl ethyl ketone, cyclohexane, cumene bydroxide, chlorobenzoyl peroxide, dicumyl, optionally in the presence of amine or cobaltic accelerators, or using ultraviolet or visible radiation using suitable sensitizers or high energy radiation.

 Compounds according to the invention are added to the known polyester resins after the synthesis during the dissolution of the oligoester or polyester in the monomer, or before the use of the polyester resins in the processing, during the mixing of the resins with the charges and the initiators.

 The compounds according to the invention, added directly after the synthesis, do not influence the stability of the finished polyester resin; they dissolve and do not precipitate in solution during storage.

 The compounds according to the invention, added either before the storage period, or directly before the use of the polyester resins for processing, do not appreciably modify the technological properties, such as the gel time and the viscosity, or the mechanical and physical properties of the resin and laminate after curing - compared with a resin that does not contain these compounds.

 If the compound of the invention is added to a polyester resin which contains paraffin, then the added product increases the adhesion between the layers executed separately from the molding of the coating or laminate and between the fibers and the resin.

Example N 1. To 100 parts by weight of unsaturated maleinophthalpropylenes polyester resin containing 38% by weight of styrene, 1 part by weight is added. Compounds described in Table 1. After carefully mixing the composition, it was run on petri dishes 95 cm2 surface, then placed in a place with air movement of 0.4 m / s and stabilized temperature 22 ± 10C. 1 hour after the beginning of the experiment, the loss of styrene is determined (Table 1).

Example N 2. To 100 parts by weight of unsaturated maleenpropylenic polyester resin containing 38% by weight of styrene was added 0.02 parts by weight of the compound described in Table 1 and 0.02 parts by weight of paraffin.

50 g of the composition thus obtained are run on a petri dish of 95 cm 2 of surface. The loss of styrene is determined after 1 hour, with the same conditions as in Example No. 1 (Table 1).

Example N 3. To 100 parts by weight of unsaturated polyester resin, containing 23% by weight of styrene and 15% by weight of methyl methacrylate, 0.01 part by weight of the compound described in Table 1 is added. monomers of the composition is determined under the same conditions as in Example N 1. The result of the measurement is shown in Table 1.

Example N 4. To 100 parts by weight of unsaturated polyester resin, containing 38% by weight of styrene, 0.05 parts by weight of the compound described in Table 1 is added. For the resulting composition, the styrene loss is determined. in the same way as in example N 1. The result of the measurement is shown in Table 1.

Example N 5. To 100 parts by weight of solution, containing 60% by weight of the compound of general formula 5, in which
X denotes a methyl group and m = 1 and 40 to the weight of styrene is added 0.1 part by weight of the compound described in Table 1. For the composition thus obtained, the styrene loss is determined in the same way as in Example No. 1. The result is given in Table 1. For comparison, the measurement result of the styrene loss for the resin without addition product is indicated.

 EXAMPLE 6 To 100 parts by weight of maleinophthalopropylene resin, containing 38% by weight of styrene, 1 part by weight of the compound described in Table 2 is added. This carefully mixed composition is made of glass fiber felt. 1003 at a weight of 600 g / m 2, a polyester-glass laminate is prepared in the following manner a fiberglass felt layer is laminated, cured and after 24 hours the following layer is interwoven. For the hardening of the thus obtained laminate, the following curing composition is used: 45% by weight of benzoyl peroxide (in pit at 50% dibutyl phthalate) and 0.25% by weight of N, N-dimethylaniline (solution with In the styrene). The gel time is about 30 minutes. The adhesion between the layers of the laminate is checked on 10 x 50 cm test pieces by the shock of a weight of 1 kg falling 25 cm in height on the test piece of the laminate, clamped vertically in a vice, so as to a part of the 40 mm test piece is above the jaws of the vise. The laminating surface (delamination) of the laminate is measured in mm 2.

Measurements are also made with other adducts, listed in Table 2.

EXAMPLE N 7. 1000 g of composition, containing the polyester resin and the compound of general formula CHCOOCH 2 CH (OH)
CH2O] nA, wherein R = C17HD3 and n = 2, A denotes formula 2, in which m = 0, are mixed according to example N 1 with 800 g of chalk, 10 g of cumyl peroxide and 70 g of glass fibers 12 mm in length.

After carefully mixing the components, the molding composition thus obtained is pressed into molds at a temperature of 150 ° C. under a pressure of 10 MPa, the pressing time being 50 s per 1 mm of thickness of the molded part. . The tensile strength of this material raises to 50 MPa and the flexural strength to 110 MPa.

Example N 8. To 100 parts by weight of unsaturated polyester resin of 2,2-di-p4- (hydroxypropoxy) phenyl propane, maleic anhydride and polyoxy-1,2-propylene diol, containing 50% by weight of styrene, 1 part by weight of the compounds described in Table 3 are added. After carefully mixing the composition, 50 g are cast on Petri dishes of 95 cm 2 of surface, placed in a place with stabilized air movement of 0.4 m / s and at a stabilized temperature of 22 ± 10C. After one hour from the beginning of the experiment, the loss of styrene is determined (Table 3).

Example N 9. To 100 parts by weight of unsaturated polyester resin of diene adduct of maleic anhydride and 2-naphthol, containing 50% by weight of styrene, is added 0.5 parts by weight of the compounds described. in Table 3. The resulting composition is cast on a bunch of
Petri dishes with 95 cm2 of surface. The loss of styrene is determined 1 hour later, under the same conditions as in the example
N 8.

Example N 10. To 100 parts by weight of maleinophthalpropylenic polyester resin, containing 23% by weight of styrene and 15% by weight of methyl methacrylate, was added by weight of the compounds described in Table 3. Loss of the monomers of the composition is determined under the same conditions as in Example N 8. The result of the measurement is shown in Table 3.

 Example No. 11. To 100 parts by weight of maleinophthalpropylenic polyester resin, containing 38% by weight of styrene, 1 part by weight of the compound described in Table 4 is added. Of the carefully mixed composition and fiber felt In the case of EM-1003 glass with a grammage of 600 g / m 2, a polyester-glass laminate is prepared in the following way: a layer of felt up to 6 mm thick is ground and cured. After 24 hours, the following layers are rubbed down to a thickness of 12 mm. For the curing of the laminate obtained in this manner, the following curing composition is used: by weight of methyl ethyl ketone peroxide and 0.35 by weight of cobalt naphthenate, containing 10% of C. The gel time is about 30 minutes. The adhesion between the layers of the laminate is dynamically controlled (ISO / R 179 - 1961) on test pieces of the 120s 15s 12mm laminate. For the strength test, supports spaced 70 mm apart and a percussion hammer of the Charpy type manufactured by the Schopper house are used. The results of the qualitative tests with some adducts are shown in Table 4.

By way of comparison, a laminate was prepared with addition of 0.05 parts by weight of paraffin and the result is shown in Table 4.

Table 1.

N, <SEP> of <SEP><SEP> Adding Products <SEP> Decreasing <SEP> Quanti- <SEP> - <SEP> Loss
<tb> the example <SEP> the evaporation <SEP> of the <SEP> monomer <SEP><SEP> of the <SEP> of
<tb> ple <SEP> product <SEP> mass
<tb><SEP> of addi
<SEP> tion
<tb><SEP> Compounds <SEP> of <SEP> formula <SEP> other <SEP> parts <SEP> g / h <SEP> g / m2
<tb><SEP> general <SEP> in <SEP> weight
<tb> for <SEP> 100
<tb><SEP> [RCOOCH2CH (OH) CH2O] nA
<tb><SEP> parten
<tb><SEP> in <SEP> which <SEP>: <SEP> weight <SEP> of
<tb><SEP> resin
<tb><SEP> R <SEP> n <SEP> A
<tb><SEP> 1 <SEP> C17H35 <SEP> 2 <SEP> formula <SEP> 2:
<tb><SEP> m = 0 <SEP> - <SEP> 1 <SEP> 0.51 <SEP> 53.6
<tb><SEP> C17H35 <SEP> 2 <SEP> Formula <SEP> 2:
<tb><SEP> m = 1 <SEP> - <SEP> 1 <SEP> 0.39 <SEP> 41.0
<tb><SEP> C17H35 <SEP> 2 <SEP> Formula <SEP> 2:
<tb> m = 2 <SEP> - <SEP> 1 <SEP> 1.05 <SEP> 110.5
<tb><SEP> 2 <SEP> C15H31 <SEP> 2 <SEP> formula <SEP> 1: <SEP> paraf- <SEP> 0.02+ <SEP> 0.85 <SEP> 89.4
<tb><SEP> fine <SEP> 0.02
<tb><SEP> 3 <SEP> C17H35 <SEP> 5 <SEP> Formula <SEP> 3:
<tb><SEP> k = 3
<tb><SEP> X = H <SEP> - <SEP> 0.01 <SEP> 1.20 <SEP> 126.3
<tb> 4 <SEP> C17H35 <SEP> 1 <SEP> -C6H5 <SEP> - <SEP> 0.05 <SEP> 1.70 <SEQ> 178.9 <SEP>
<tb> 5 <SEP> C17H35 <SEP> 2 <SEP> formula <SEP> 2:
<tb><SEP> m = 1 <SEP> - <SEP> 0.1 <SEP> 1.05 <SEP> 110.5
<tb><SEP> - <SEP> - <SEP> - <SEP> - <SEP> - <SEP> 1.90 <SEP> 200.0
<Tb>
Table 2.

<SEP> N) <SEP> of <SEP> Products <SEP> of addition <SEP> decreasing <SEP> Quantity <SEP> Surface <SEP> of
<tb><SEP> the former <SEP> Evaporation <SEP> of the <SEP> monomer <SEP> of the product <SEP> Laminating
<tb><SEP>SEP><SEP> example of <SEP> stratum <SEP>
<tb><SEP> edition <SEP>
<tb><SEP> Compounds <SEP> of <SEP> Formula <SEP> Other <SEP> Parts <SEP> mm
<tb><SEP> general <SEP> in <SEP> weight
<tb> for <SEP> @@@
<tb><SEP> [RCOOCH2CH (OH) CH2O] nA
<tb><SEP> parts
<tb><SEP> in <SEP> which <SEP>: <SEP> in <SEP> weight
<tb><SEP> R <SEP> n <SEP> A <SEP> of <SEP> Res <SEP>
<tb><SEP> 6a <SEP> C17H35 <SEP> 2 <SEP> Formula <SEP> 2: <SEP> 1 <SEP> 220
<tb><SEP> m = 1 <SEP> - <SEP> 1 <SEP> 220
<tb><SEP> b <SEP> C17H35 <SEP> 2 <SEP> Formula <SEP> 2:
<tb> m = 0 <SEP> - <SEP> 1 <SEP> 157
<tb><SEP> c <SEP> C17H35 <SEP> 1 <SEP> -C6H5 <SEP> - <SEP> 1 <SEP> 127
<tb> d <SEP> C17H35 <SEP> 2 <SEP> formula <SEP> 2:
<tb><SEP> m = 2 <SEP> - <SEP> 1 <SEP> 177
<tb><SEP> e <SEP> C17H35 <SEP> 2 <SEP> - "- <SEP> paraf- <SEP> 1 + 0.05 <SEP> 297
<tb><SEP> fine
<tb><SEP> f <SEP> C17H35 <SEP> 1 <SEP> -C6H5 <SEP> paraf- <SEP> 1 + 0.05 <SEQ> 178
<tb><SEP> fine
<tb><SEP> g <SEP> - <SEP> - <SEP> - <SEP> paraf- <SEP> 0.05 <SEP> 442
<tb><SEP> fine
<tb> h <SEP> - <SEP> - <SEP> - <SEP> - <SEP> - <SEP> 173
<Tb>
Table 3.

of <SEP> of <SEP> | <SEP> Products <SEP> of addition <SEP> decreasing <SEP> quantity <SEP> Loss
<tb><SEP> the evaporation <SEP> of the <SEP> monomer <SEP> of the <SEP> pro <SEP> of
<tb>'exem
<tb><SEP> duit <SEP> mass
<tb><SEP> of addi
<tb><SEP> tion
<tb><SEP> Compounds <SEP> of <SEP> Formula <SEP> General <SEP>: <SEP> Parts <SEP> g / h
<tb><SEP> [RCOOCH2-CH (OH) CH2O] <SEP> nA <SEP> in <SEP> weight
<tb><SEP> in <SEP> which <SEP> @ <SEP><SEP> for <SEP> 100
<tb><SEP> in <SEP> which <SEP>: <SEP> parts
<tb><SEP> in <SEP> weight
<tb><SEP> of <SEP> resin
<tb> 8 <SEP> C17H35 <SEP> 1 <SEP> n-C4H9 <SEP> 1 <SEP> 0.95
<tb><SEP> C17H35 <SEP> 1 <SEP> CH2 = CH-CH2 <SEP> 1 <SEP> 1.10
<tb><SEP> C17H35 <SEP> 1 <SEP> C7H15C <SEP> 1 <SEP> 0.90
<tb><SEP> C15H31 <SEP> 2 <SEP> - (CH2) 4 <SEP> 1 <SEP> 0.51
<tb><SEP> C17H35 <SEP> 2 <SEP> -CH2-CH = CH-CH2- <SEP> 1 <SEP> 1.05
<tb><SEP> C17H35 <SEP> 2 <SEP> -CH2-CH2-O-CH2-CH2- <SEP> 1 <SEP> 1.24
<tb><SEP> - <SEP> - <SEP> - <SEP> - <SEP> - <SEP> - <SEP> 1.67
<tb><SEP> C15H31 <SEP> 2 <SEP> CH2CH2- [OCH2CH (CH) CH2OCH2CH2] <SEP> 0.5 <SEP> 0.60
<tb><SEP> C17H35 <SEP> 2 <SEP> -CH2CH2-O-CH2CH2- <SEP> 0.5 <SEP> 0.75
<tb><SEP> C17H35 <SEP> 2 <SEP> - (CH2) 4- <SEP> 0.5 <SEP> 0.64
<tb><SEP> C15H31 <SEP> 2 <SEP> -OC- (CH2) 6-CO- <SEP> 0.5 <SEP> 0.50
<tb><SEP> - <SEP> - <SEP> - <SEP> - <SEP> 1.49
<tb> 10 <SEP> C17H35 <SEP> 2 <SEP> -CH2CH2-OCH2 (CH) CH2OCH2CH2- <SEP> 1 <SEP> 0.43
<tb><SEP> C17H35 <SEP> 2 <SEP> - (CH2) 4- <SEP> 1 <SEP> 0.35
<tb><SEP> C17H35 <SEP> 1 <SEP> C7H15-CO- <SEP> 1 <SEP> 0.90
<tb><SEP> C17H35 <SEP> 1 <SEP> C4H9 <SEP> 1 <SEP> 0.85
<tb><SEP> - <SEP> - <SEP> - <SEP> 1.45
<Tb>
Table 4

of <SEP> of <SEP> | <SEP> Products <SEP> of addition <SEP> decreasing <SEP> quantity <SEP> Result <SEP>
<tb> evaporation <SEP> of <SEP> monomer <SEP> of <SEP> pro <SEP> of <SEP> es
<tb> the exem
<SEP>duitd'ad-<SEP> sai <SEP> dy
<tb> ple <SEP> edition <SEP> namic
<tb><SEP> Product <SEP> according to <SEP> the invention <SEP> Other <SEP> parts
<tb> in <SEP> weight
<tb><SEP> in <SEP> which one
<tb><SEP> for <SEP> 100
<tb><SEP> parts
<tb><SEP> in <SEP> weight
<tb><SEP> R <SEP> n <SEP> A <SEP> of <SEP> resin
<tb><SEP> 11 <SEP> C17H35 <SEP> 2 <SEP> -CH2CH2OCH2CH2- <SEP> - <SEP> 1 <SEP> absence <SEP> of
<tb><SEP> take off
<tb><SEP> to <SEP> the place
<tb><SEP> of <SEP> division
<tb><SEP> of <SEP> the thick
<tb><SEP> seur <SEP> of
<tb><SEP> laminate
<tb><SEP> 11 <SEP> C15H31 <SEP> 2 <SEP> - (CH2) 4 <SEP> - <SEP> 1 <SEP> absence <SEP> of
<tb><SEP> take off
<tb><SEP> to <SEP> the place
<tb><SEP> of <SEP> division
<tb><SEP> of <SEP> the thick
<SEP> seur <SEP> of
<tb><SEP> laminate
<tb><SEP> - <SEP> - <SEP> - <SEP> paraf- <SEP> 0.05 <SEP> takeoff <SEP> to
<tb><SEP> fine <SEP> the place
<tb><SEP> of <SEP> division <SEP> of
<tb><SEP> the thickness
<tb><SEP> of the <SEP> statified
<Tb>
Of course, the invention is not limited to the embodiments described and shown, which have been given by way of example. In particular, it comprises all the means constituting technical equivalents of the means described, as well as their combinations, if they are executed according to its spirit and implemented in the context of protection as claimed.

Claims (3)

R E V E N D I C A T IO N S  1. Additive for reducing and limiting the evaporation of one or more crosslinking monomers during the crosslinking reaction of an unsaturated oligoester or polyester dissolved in the one or more crosslinking monomers. - lants, characterized in that said additive is a compound or a mixture of compounds of general formula [@ -COOCH @ -CH (OH) -CH-O] @  Wherein R represents a preferably unbranched group, alkyl, alkenyl, alkadienyl, hydroxyalkyl or hydroxyalkenyl, containing from 12 to 22 carbon atoms; and wherein:  a) when n is 1, A represents a phenyl group, or a phenyl group substituted ortho and / or para by CH3 or chlorine atoms, or one of the aforementioned groups substituted with a -CO- radical, or a linear or branched alkyl, alkylcarbonyl, alkenyl group containing from 2 to 8 carbon atoms;  b) When n is 2, A represents a p-phenylenic, meta-phenylenic group, or the ortho-, para-, or meta [-CO-C6H4-CO-] group, or the ortho radical--CO- C6H10-CO-), or a group of general formula

 wherein rn ranges from 0 to 4, or a group of general formula -OC- (CH2) p-CO- with p ranging from 2 to 8, or a group of formula -A1 [-O-CH2-CH (CH2Cl) ], in which A1 denotes an alkylene group containing from 2 to 6 carbon atoms and r varying from 0 to 3, or a group of formula -A 2 R O-A2 ## where A2 denotes a linear or branched alkylene group containing from 2 to 4 carbon atoms. preferably carbon radicals -CH2-CH2- or -CH2-CH (CH3) - and where s is 1 or 2;  c) and when n takes the values from 2 to 8, A denotes a group of general formula

 wherein X is hydrogen or -C (CH3) 3 and k is 0 to 6.  2. A process for producing unsaturated polyester resins, comprising the steps of dissolving an unsaturated oligoester or polyester in one or more crosslinking monomers, introducing an additive to reduce and limit the evaporation of the monomer (s) during the crosslinking reaction, optionally adding inhibitors, fillers, initiators or the like, characterized in that said additive for reducing and limiting the evaporation of the crosslinking monomer (s) is a compound or a mixture of compounds according to claim 1 .  3. A process according to claim 2, characterized in that added to 100 parts by weight of resin 0.005 part to 5 parts by weight of the abovementioned additive reduction and evaporation limitation.