NO864949L - MIXTURES OF UNSATURED POLYESTERS OR POLYESTERAMIDS AND EFFECTIVE FLEXIBILIZERS FOR THESE. - Google Patents

Description

Unsaturated polyester resins are well-known compounds for many purposes. The extensive literature on polyesters is summarized in Volume 18 of the Encyclopedia of Chemical Technology (Kirk-Othmer; 3rd ed.) at pages 575-594. Later developed, but also well-known and very applicable are the unsaturated polyesteramide resins. (The "resins" referred to are actually mixtures of the polyester or polyester amide kyds with non-resin vinyl monomers such as styrene).

It is well known that the latter resins could be improved in several respects. They typically undergo strong shrinkage during curing, and the cured resins have relatively low impact strengths and percent elongations. US Patent No. 3,448,172 - which is believed to be the closest prior art to the invention - describes significant improvement in flexural strength and shrinkage of unsaturated polyester resins by adding relatively large amounts of certain "high molecular weight urethane polymers with an ordered arrangement of side group unsaturation". However, the urethane polymers are relatively difficult to manufacture and - judging from the examples in the patent - the amount of urethane polymer used must be approximately equal to the amount of the alkyd component to achieve the required improvement.

The primary objective of the present invention is to provide a less complicated and more effective flexibilizer for unsaturated polyester and polyesteramide resins.

A further aim is to provide as such flexibilizers, vinyl-terminated urethane oligomers (as defined below) which are very effective in flexibilizer/alkyd weight ratios down to approx. 7/100.

Another aim is to provide binary mixtures of the aforementioned flexibilizers with polyester or polyester amidal alkyls, from which the improved resins according to the invention can be prepared by adding a non-resin vinyl monomer (reactive diluent).

A particular aim is to provide flexibilized polyester and polyesteramide resin mixtures, which on curing show higher impact strengths, toughnesses and percentage elongations than the unflexibilized resins in and of themselves.

Still further objectives will be apparent to those skilled in the art from

the following description and requirements.

The foregoing objectives are achieved by using as a flexibilizer component branched or linear polymer molecules of relatively low molecular weight built up of "polyglycol" and "urethane" units and terminated at at least one end of a group which is vinyl reactive (ie contains a polymerizable carbon -to-carbon double bond).

The invention can be defined as a flexibilizer/alkyd mixture that does not phase separate during curing, comprising:

a. an unsaturated polyester and/or polyester amidalkyd which

does not contain any terminal polycycloalkenyl groups, and

b. from 1 to 20 parts by weight of a flexibilizing agent comprising one or more urethane oligomers per 100 parts of the alkyd, which oligomers each have at least one vinyl-reactive end group and are an addition product of a polyether glycol with an unsaturated isocyanate or with a diisocyanate and an unsaturated compound comprising a -NCO or -Ct^OH group, c. from 0 to 400 parts by weight of a non-resin vinyl monomer per 100 parts of the alkyd, with the general proviso that when the alkyd comprises an unsaturated polyester, each of the parts by weight of the oligomer per 100 parts alkyd not exceeding ll + 9a/(a+e) , where a and e are the respective parts by weight of the polyester amide and the polyester in the mixture,

or

the unsaturated compound is an unsaturated isocyanate, an alkenylphenol, a hydroxyalkyl acrylate initiated polyglycol or N-methylolacrylamide.

The term "polyester" shall not here include the so-called "vinyl ester resins" (adducts of vinyl-reactive carboxylic acids with epoxides).

Unexpectedly, the flexibilizing effect of the above-mentioned oligomers on isophthalate alkyds has been found to be significantly greater than on orthophthalate alkyds.

In one method aspect, the invention can be defined as the method for preparing the present mixtures where the oligomer is mixed with the alkyd, one or both of which may be in the form of a preformed mixture with a non-resin vinyl monomer.

Suitable polyesters and polyester amides

The unsaturated polyesters which are suitable for carrying out the invention are those which at least partially derive from unsaturated polycarboxylic acids (maleic acid for example) and polyhydroxy compounds (propylene glycol for example). The unsaturated polyester amides are those which can be similarly derived from the same unsaturated acids, the same polyols and, in addition, polyfunctional amines.

The preferred polyesters can be defined by having an ester chain in the middle, comprising:

(a) dioxy groups of the formula:

wherein is a divalent organic radical selected from alkylene, oxy-linked alkylene, oxy-linked arylene, cycloalkylene, polycycloalkylene, bis(alkyl)cycloalkylene, bis(alkyl)polycycloalkylene and arylene, and mono-to-trihydroxyalkylene; and (b) diacyl residues of difunctional carboxylic acids, at least a part of these acids being α,Ø-unsaturated acids and a possible residue being saturated aliphatic acids, aromatic acids or mixtures thereof.

Similarly, preferred polyester amides may be defined as those having an ester amide chain in the middle comprising:

(a) diamino groups of the formula

where R 1 and R are independently selected from hydrogen, aliphatic, cycloaliphatic and aromatic groups or R<1> and R<3> together form an aliphatic ring, and R<2> is a

divalent organic radical selected from alkylene, oxy-bonded alkylene, oxy-bonded arylene, alkyleneamino-bonded alkylene, alkyleneamino-bonded cycloalkylene, cycloalkylene, polycycloalkylene, arylene, alkylarylene-bis(alkyl)cycloalkylene and bis(alkyl)polycycloalkylene,

(b) dioxy groups of the formula:

where R 4 is a divalent organic residue selected from alkylene, oxy-linked alkylene, oxy-linked arylene, cycloalkylene, polycycloalkylene, bis(alkyl)cycloalkylene, bis(alkyl)polycycloalkylene, and arylene, and mono- to trihydroxyalkylene; and (c) diacyl residues of divalent carboxylic acids, of which at least part of the acids are α,3-unsaturated acids and any residue is saturated aliphatic acids, aromatic acids or mixtures thereof.

Typical diamine components in the preceding polyester amides are ethylenediamine, propylenediamine, hexane-1,6-diamine, piperazine, 4,4'-methylene-bis(cyclohexylamine), 2,2'-bis(4-aminocyclohexyl)propane, 4, 4'-diaminodiphenyl ether, bis(aminomethyl)norbornane, toluenediamine, bis(aminomethyl)dicyclopentadiene and homopiperazine. Typical polyamines are aminoethylpiperazine and diethylenetriamine.

The polyol component of the polyester or polyester amide is from the class with the formula:

where R^ is as defined above. Mixtures of two or more such polyols can be used.

Representative such polyols are ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, dicyclopentadiene dimethanol, bis(hydroxymethyl)norbornane, methylcyclohexanedimethanol, bis(hydroxypropyl)bisphenol A and other hydroxyalkylated bisphenols, pentaerythritol, sorbitol, glycerol and polypropoxylates of glycerol.

When a polyester amide is to be used, the ratio of diamine to polyol therein can be varied within wide limits. The latter ratio is significantly related to the solubility of the modified polyester amide in reactive diluents such as styrene, which are often used with polyester amides for many purposes. As a general rule, the moles of diamine should not exceed approx. 1/3 of the combined moles of polyol and diamine. The structure and size of the diamine molecule will largely determine the maximum amount of diamine that can be used.

The unsaturated polycarboxylic acid component in the polyester or polyester amide is preferably mainly composed of an α,O-unsaturated acid such as maleic acid, fumaric acid, maleic anhydride or mixtures of such compounds. The latter acids are easily available, are highly reactive with the polyol and/or polyamine, and lead to products with good properties.

A portion of the α,/3-unsaturated acid can further be replaced with a saturated or aromatic polycarboxylic acid to vary the cross-linking potential and physical properties of the modified polyester or polyesteramide. Such acids include the aliphatic acids such as adipic acid and the aromatic acids such as isophthalic acid. Replacement of part of the α,/3-unsaturated acid with such acids is common within the polyester technique. Appropriate selection of the acid and the amount thereof to achieve a desired goal will be known to the person skilled in the art and can be optimized by simple prior experiments.

Although not preferred, endomethylene tetrahydrophthalic acid or -anhydride can also be used. The corresponding methyl-endomethyl-ene tetrahydrophthalic anhydride or acid can be used instead of or in admixture with the unsubstituted anhydride or acid.

Procedures for the production of the preceding alkyds are well known and shall only be summarized here as follows.

The total amount of acid varies as a function of the total polyol and polyamine components used. In general, one equivalent of dicarboxylic acid requires 1.00 to 1.10 equivalents of diol or diol/diamine mixture.

The unsaturated polyesters or polyesteramides are produced by fusion reaction of the α,3-unsaturated polycarboxylic acid and the polyol (polyamine) components while removing water. Other alternative methods will be well known to those skilled in the art.

For example, unsaturated polyesters or polyester amides are produced by reaction of the α,/3-unsaturated polycarboxylic acid and monoepoxides as total or partial glycol replacements. Finally, although less preferred, diesters of α,O-unsaturated dicarboxylic acids and polyols can be reacted in a transesterification reaction to give unsaturated polyesters.

Suitable urethane oligomers

The flexibilizer component in the mixtures according to the invention is a polyglycol residue-comprising urea ethanol oligomer with at least two end groups, of which at least one is vinyl reactive. The oligomer can be branched or linear, but does not contain significant proportions of types with side-standing and terminal vinyl groups. Preferably, it has only one to a few branches and does not include any types with vinyl side groups.

The term "side" as used here means a vinyl group linked to an oligomeric chain through a relatively short linking group which is itself non-oligomeric, i.e. not made up of repeating units. In contrast, "terminal" vinyl groups are found only at the ends of oligomeric chains - ending at the opposite ends either in chain to other oligomer chains or in vinyl groups.

The oligomers of this type are described (as "monomers") in US Patent Nos. 3,297,745 and 4,360,753 and are generally suitable for the practice of the present invention. Similar oligomers, where the end groups are included as hydroxyalkyl acrylate initiated polyglycols rather than hydroxyalkyl acrylates per se, are not only suitable, but advantageous in the flexibilizer role.

Suitable oligomers are also the bis(N-vinyl carbamates) which are formed by reacting an unsaturated isocyanate with a polyglycol. Suitable such isocyanates are vinyl isocyanate and isopropenyl isocyanate - as described in US patent no. 3,598,866; see example 8 therein. In a similar way, polyadducts of isocyanatoethyl methacrylate, allyl isocyanate, allyl isothiocyanate or allyl glycidyl ether with polyglycols can also be used as flexibilizer component.

The flexibilizing agent component in the mixtures according to the invention can alternatively be of the new type described in US patent no. 4,486,582, issued 4 December 1984. This type of flexibilizing agent is produced by reacting a vinyl- or acryloxy-substituted phenol or phenol-initiated polyol with at least one of the terminal isocyanate (or isothiocyanate) groups in a urethane oligomer formed by reacting an excess of a divalent isocyanate (or thiocyanate) with a polyol. The preferred vinyl-substituted phenol for this purpose is phenol itself, substituted with an isopropenyl group. However, such other phenols as cresols ring-substituted with ethenyl, allyl, or isopropenyl groups are also suitable, and the polyol portion of some or all of the molecules may be terminated with an "N1" group.

The generally most suitable and economical flexibilizers currently known are oligomer reaction products of (1) a diisocyanate, (2) a hydroxy or aminoalkyl acrylate, and (3) a polyglycol or amino-terminated polyglycol. In these oligomers, the alkyl part of the hydroxy or aminoalkyl acrylate may be interrupted by one or more oxygen or sulfur atoms; ie the hydroxy-substituted acrylate can be a monoacrylate of diethylene glycol or tripropylene glycol for example. Also N-methylolacrylamide can be used instead of a hydroxyalkyl acrylate as a source of vinyl end groups in such oligomers.

Similarly, the vinyl reactive end group(s) of the oligomer may be derived from an alkenyl amine which is N-substituted with a hydroxy terminated group; for example, the adduct of from one to several molecules of an alkylene oxide with vinyl, diallyl or divinylamine can be reacted with the isocyanate end groups in a polyol/diisocyanate reaction intermediate.

In each of the preceding types of unsaturated adducts, the polyglycol residue preferably originates from a diol (by base-catalyzed reaction with an alkylene oxide), but is desirably based on

(beginning with) a triol - such as glycerol or triethanolamine, for example - , or on an amino alcohol or a polyfunctional amine. Since isocyanates will react with -NH, as well as with -OH (or -SH) groups, the polyglycol unit(s) may be amino terminated and/or the -OH function in an end group precursor - such as 2-hydroxypropyl methacrylate, for example - may be replaced with a -NH2 group.

Preferably, the oligomer has at least two vinyl-reactive end groups. However, this is not absolutely required; the types with only one vinyl-reactive end group are also considered suitable for carrying out the present invention. On the other hand, a total of three terminal vinyl groups (derived from the use of a triol-based polyglycol) is considered advantageous.

All branches of the flexibilizer component are of course within the scope provided that the oligomer(s) show the required degree of compatibility with the other components (alkyd or alkyd and vinyl monomer components) in the cured mixture according to the invention. This can be easily investigated for all oligomer candidates without too much experimentation in a manner that will be known to a person skilled in the art.

Production methods of flexibilizers

The vinyl-terminated urethane oligomers described in US Patent Nos. 3,297,745 and 4,360,653 are generally suitable for use as flexibilizers in the present invention and can be prepared by several methods described in these patents.

The latter methods are generally also applicable for the preparation of oligomers in which the end unsaturation originates from a hydroxyacrylate-initiated polyol or a phenol-initiated polyol in which the phenol is ring-substituted with an alkenyl group.

Production of oligomers by reaction of an unsaturated isocyanate, such as isopropenyl isocyanate, allyl isothiocyanate and isocyanate ethyl methacrylate for example, with a polyglycol is exemplified here and does not require any methods with which polyurethane chemists are not familiar.

When producing oligomers by condensation of a hydroxy or aminoalkyl acrylate, a diisocyanate and a polyglycol, it is not critical whether the isocyanate is first reacted with the acrylate or the polyglycol. In both cases, however, the reactant ratio in the condensation compound must be controlled to ensure the presence of the necessary, unconverted isocyanate end groups in the intermediate product.

The reaction order affects and can be used to manipulate the viscosity (average molecular weight) of the flexibility agent. If the isocyanate is first reacted with the hydroxyacrylate, the viscosity of the final product will be lower than when the isocyanate is first reacted with the polyol.

Flexibilizer content

The percentage by weight of the oligomer in the alkyd/vinyl monomer mixtures according to the invention can vary from 1 to 10%.

Preferably, however, the content of the flexibilizer in the mixture is from 4 to 8%, ranges from 5 to 7.5% being particularly preferred. In any case, the content of flexibilizer is preferably such that "phasing", i.e. formation of a visibly defined second phase, does not occur when the mixture hardens.

Copolymerizable vinyl monomer

The mixtures according to the present invention preferably comprise a non-resin-containing, vinyl-reactive monomer - which is preferably styrene. Other such special monomers are, for example, vinyltoluene, t-butylstyrene, divinylbenzene and chlorostyrene. Various acrylates exemplified by di-cyclopentadienyl acrylate, sec-butyl acrylate and ethyl acrylate are, albeit less preferred, considered suitable for carrying out the present invention. Thus, suitable vinyl monomers are generally those which are normally copolymerized with polymers having terminal or lateral vinyl-reactive, olefinic or cyclo-olefinic double bonds. Such monomers have previously been well documented.

The well-known catalysts and methods for the latter type of copolymerization are also generally applicable for "curing" (chain extension and cross-linking) of the compositions according to the present invention comprising vinyl monomers. Such mixtures which do not contain vinyl monomers are considered novel in themselves and can be cured using the same catalysts and methods for thermosetting products.

The vinyl monomer which is often called a reactive diluent can be used within a wide concentration range from 20 to 80% diluent to 80 to 20% of the polyester or polyester amide (from 25 to 400 pha (parts per 100 parts alkyd)). The optimum amount will depend largely on the individual alkyd, diluent and desired properties in the uncured and cured state, but will often be 50-80 pha. Reactive diluents are mainly used to adjust the viscosity of a resin mixture to make it easier to use in a given fabrication method. A coating formulation will normally require a lower viscosity than a casting formulation.

When the diluent is styrene, its content is

preferably from 60 to 70 pha.

The weight ratio of the flexibilizer component to the alkyd component in the alkyd/vinyl monomer mixtures according to the invention can vary from 1/80 to 1/5, i.e. from 1-20 pha. Preferably, the ratio lies within the range from 1/50 to 8/50, or from 2 to 16 pha.

Other additives that are common in the polyester and polyester-amide area can also be included in formulations that are based on the flexible alkyds. Thus, fillers, pigments and other dyes, reinforcing fibers and other additives can be added to serve their intended function.

The flexible polyesters and polyester amides can be cured by known catalyst systems. Peroxides, such as methyl ethyl ketone peroxides can be used with or without known promoters, such as cobalt octoate or cobalt naphthenate, which work with such peroxides. Acyl peroxides such as benzoyl peroxides can be used with or without promoters such as tertiary amines, typically including dimethylaniline and N,N-dimethyl-p-toluidine. The concentrations of catalyst and promoter are adjusted within known limits from 0.1 to 3.0% by weight depending on the desired curing speed, the magnitude of the heat generation that occurs and for other known reasons. Known gel retarders, such as p-benzoquinone, can be used in the curing system.

The flexible resin mixtures according to the present invention are particularly suitable for use in applications that require improved flexibility in connection with increased impact resistance as well as reduced shrinkage after curing ("low profile"). Typical for these purposes are volume and plate casting connections

and the parts produced from these compounds.

The non-cured alkyd/flexible agent mixtures according to the invention which do not contain vinyl monomers (such as, for example, styrene) are useful as intermediate materials which can be mixed with such monomers and cured.

Examples

The following examples are intended to illustrate the invention and should not be considered as limiting the present invention in a way that does not correspond to the requirements in connection with these specifications.

The materials with capital letters in the examples are registered trade names.

Where appropriate, the flexibilizers are called "VRPs" in the following (vinyl-reactive plasticizers).

I. Production of flexibilizers (Not examples according to the invention)

A(1) Preparation of a VRP from a polypropylene glycol, toluene diisocyanate and hydroxypropyl acrylate.

A VRP with the statistical structure (A-I)

was produced in two stages; the polyglycol was reacted with the diisocyanate in the presence of tin(II) octoate until the -OH band in the infrared (IR) spectrum of the reaction mixture disappeared, and hydroxyacrylate was added to finish reacting the remaining isocyanate groups. The detailed procedure follows. A 0.12% solution of stannous octoate (3.355 grams) in 2811.12 grams (1.4056 g mol) of polypropylene glycol (DOW: P-2000) was added over a period of approx. 1 3/4 hours to 488.4 g (2.8111 g mol) toluene diisocyanate (type I, NACONATE 80; registered trade name of The Dow Chemical Company) 80/20 mixture of 2,4- and 2,6-isomers ) in a 5-liter resin flask equipped with a reflux condenser and a stirrer. The flask contents were heated from an initial temperature of 60°C to a final temperature of 70°C during the addition. Stirring was continued at the latter temperature for a further 3/4 hour, at which time the -0H infrared peak had disappeared. The preformed solution of 1.815 g of phenothiazine (vinyl polymerization inhibitor) in 330 g (2.54 g mol) of 2-hydroxypropyl acrylate was then added and the resulting mixture stirred at a temperature of 82-86°C for a further 2/3 hour, at which point no further decrease in isocyanate absorption (IR) or increase in carbonyl absorption could be observed. The product referred to herein as VRP-A had a Gardener viscosity at 20°C equal to 79,200 eps.

A(2). Preparation of a VRP with an ideal structure containing two polyglycol units and three diisocyanate units.

A mixture of 24 73 g (1.2365 gram-mol) polypropylene glycol (P-2000) and 1 g tin(II) octoate was added with stirring to a mixture of 330 g (1.897 g mol) toluene diisocyanate (80/20- mixture of 2,4- and 2,6-isomers) and 0.465 g of tin (II) ^-octoate and stirring was continued until the reaction was complete (-OH IR absorption disappeared). 162.5 g (1.25 g mol) of 2-hydroxyethyl acrylate (and a small amount of methyl ethyl hydroquinone vinyl stabilizer) was then stirred into the reaction mixture and allowed to react until -OH IR absorption was minimized and urethane carbonyl absorption was maximized. A small amount of toluene diisocyanate was added to completely react the last -OH, and then the remaining -NC0 was completely reacted by adding approx. 0.5-1.0 g isopropanol. The resulting product, a very viscous, clear light yellow liquid, was then diluted with styrene to a solution with 80% by weight VRP content, herein referred to as "VRP-A2".

A(3-6). Production of a number of types A VRP' is ongoing

use of polyglycols with different molecular weights and/or composition.

Toluene diisocyanate (2.0 mol) and phenothiazine (0.05%) were added to a reactor and heated to 60°C with stirring. The diisocyanate used was an 80/20% by weight mixture of the 2,4 and 2,6 isomers respectively. Hydroxypropyl acrylate (2.0 mol) was mixed with stannous octoate catalyst (0.12 wt%), and this mixture was added to the reactor over a period of 1.5 to 2 hours. The reaction was allowed to proceed at 60°C reaction temperature until infrared spectrophotometric analysis of a film sample of the reaction product showed substantially complete reaction (the hydroxyl group disappeared), typically 2.0 to 3.0 hours. At this point, the polyglycol component was added in an amount which gave 1.0 mol of reactive hydroxyl groups. The polyglycol component was selected from the following:

(3) polypropylene glycol of 1200 average molecular weight,

(4) polypropylene glycol of 2000 average molecular weight,

(5) 4000 average molecular weight polypropylene glycol, or (6) 3000 average molecular weight adduct of glycerol and a 92.0% propylene oxide-8.0% ethylene oxide mixture.

The reaction was continued at 60°C temperature until infrared spectrophotometric analysis showed substantially complete reaction (the isocyanate and hydroxyl groups had disappeared), typically 3.0 to 4.0 hours. The reactor was cooled and the vinyl reactive plasticizer recovered and named VRP-(A4),

-(A5), etc.

Remark:

The polyglycol with a molecular weight of 400 contained approx. 30% by weight of a type with only one hydroxy end group, the other end group being

B. Preparation of VRP' is from isocyanatoethyl methacrylate and a polyol.

(1) 80.4 g (0.52 g-mol) isocyanatoethyl methacrylate,

519.6 g (0.26 g mol) of P-2000, 0.66 g of stannous octoate (catalyst) and 0.05 g of phenothiazine (vinyl stabilizer) were stirred together in a round stoppered flask for 3 hours. The turnover proceeded completely spontaneously, i.e. without heating. The resulting VRP showed a low viscosity and had the statistical structure (B-1):

(2) A higher molecular weight VRP was prepared in two steps. 25.2 g (0.145 g mol) toluene diisocyanate (type I

NACONATE 80) was added slowly to a solution of 0.69 g of stannous octoate in 574.8 g (0.2874 g mol) of P-2000. After stirring for several hours, the resulting glycol-extended diurethane was reacted with 44.5 g (0.287 g mol) of isocyanatoethyl methacrylate as in (1) above. The resulting VRP was considerably more viscous than that obtained in preparation B-(1) and had the statistical structure (B-2): (3) Preparation of type (1) oligomers at higher temperatures.

Isocyanatoethyl methacrylate (1.0 mol) was added to a reactor and heated to 70°C with stirring. Polypropylene glycol of average molecular weight 2000 was mixed with stannous octoate catalyst (0.10% by weight) and a sufficient amount was added to the reactor to provide 0.50 mol of reactive hydroxyl groups. The reaction continued at 70°C temperature for 30 minutes. At this point, infrared spectrophotometric analysis showed essentially complete conversion (the isocyanate and hydroxyl groups had disappeared). The reactor was cooled and the vinyl reactive plasticizer (VRP B3) recovered.

C. Preparation of a vinyl-terminated urethane-

oligomer ("VRP-C") comprising isopropenylphenol-derived end groups.

Toluene diisocyanate (0.255 mol, 44.41 g), p-isopropenylphenol (0.255 mol, 34.21 g) and phenothiazine (0.055 wt%, 0.167 g) were added to a glass reactor and maintained under a nitrogen atmosphere with stirring. The toluene diisocyanate was an 80 to 20% by weight mixture of the 2,4- and 2,6-isomers, respectively. The p-isopropenylphenol contained less than 1.6% by weight of dimer and only traces of phenol residue. The reactants were heated to 45°C. A catalyst pack consisting of an organotin salt available from Witco Chemical Co. as FOMREZ UL-28 (0.152 g) and a tertiary amine commercially available from Abbot Labs as POLYCAT DBU (0.152 g) were added to the stirred slurry and external cooling of the reactor was started. A maximum exotherm to 82°C occurred 4 minutes later. Cooling reduced the temperature of the reactor contents to 60°C, and this temperature was maintained for 56 minutes. At this point, infrared spectrophotometric analysis of a film sample of the transparent pale yellow colored reaction product showed that the reaction of the isocyanate with the phenolic hydroxyl was essentially complete (hydroxyl group disappeared, carbonyl group appeared). Polypropylene glycol (0.1275 mol, 225.0 g) with an average molecular weight of 2000 was added to the reactor, followed by the addition of more catalyst, Witco F0MREZ UL-28 (0.076 g) and POLYCAT DBU (0.152 g). A maximum exotherm to 68°C occurred 11 minutes later. Cooling reduced the reaction temperature to 65°C, and this reaction temperature was maintained for 3.8 hours. At this point, infrared spectrophotometric analysis of a film sample of the white-colored, viscous, liquid reaction product showed that the reaction of the remaining isocyanate groups with the aliphatic hydroxyl groups was complete. The reactor contents were cooled and a vinyl-reactive "oligomer" (VRP-C) with the following statistical formula (C)

was mined:

D. Preparation of a VRP comprising alkylene oxide-extended hydroxy functional acrylate end groups.

Polypropylene glycol (0.06375 mol, 127.5 g) having an average molecular weight of 2000 and containing dissolved tin (II) octoate (0.1105 g) and an organotin salt which can be purchased from Witco Chemical Co. as FOMREZ UL-28 (0.1105 g) was added over a 1 minute period to a glass reactor containing stirred toluene diisocyanate (0.1275 mol;;, 22.21 g) under a nitrogen atmosphere. The toluene diisocyanate used was an 80 to 20% by weight mixture of the 2,4 and 2,6 isomers respectively. A maximal exotherm to 51°C occurred 3 minutes later; then the reaction temperature was increased to 60°C. After 44 minutes at 60°C reaction temperature, infrared spectrophotometric analysis of a film sample of the transparent reaction product showed that the reaction of the isocyanate with the aliphatic hydroxyl group was complete (hydroxyl group disappeared, urethane carbonyl group appeared). 51.19 g (0.1275 mol) of the mono(2-hydroxyethyl acrylate) ether of pentapropylene glycol-1,2 was then added. The reaction temperature was maintained at 60°C and after 78 minutes, infrared spectrophotometric analysis of a film sample of the transparent reaction product showed that the reaction of the remaining isocyanate groups with the aliphatic hydroxyl groups was complete. Hydroquinone (100 ppm) was added to the reactor and the resulting VRP (here called VRP-D) was recovered.

The oligomer (VRP-D) had the statistical structure (D):

II; Representative alkyd preparations

(Not an example according to the invention)

1. An orthophthalic polyester was prepared as follows: Maleic anhydride (323.60 g, 3.30 mol) and phthalic anhydride (325.86 g, 2.20 mol) were added to a reactor and heated to a white-colored stirred slurry held at 100°C under a nitrogen atmosphere. Propylene glycol (460.41 g, 6.05 mol) was added and a maximum exotherm of 140°C resulted 19 minutes later. At this point, nitrogen flushing was increased to 0.5 1 per minute, a steam condenser was started and temperature control one was set at 160°C. That temperature was reached 5 minutes later. After 2 hours the temperature control was set to 205°C, and this temperature was reached 32 minutes later. After 8 hours at 205°C reaction temperature, a total of 103 ml of an aqueous layer had collected in a Dean Stark trap. The reactor was cooled to 165°C and 100 ppm hydroquinone added. The unsaturated polyester alkyd was recovered as a clear, transparent solid with a final acid number of 27.2. It was called alkyd 1.

III. Examples according to the invention

In each of the following examples, styrene/alkyd blends containing and not containing a VRP were prepared and compared for physical and mechanical properties.

Example 1

Portions of the preceding alkyd (1) were mixed with styrene and VRP-A1 in amounts indicated in the following table:

The resin formulations (1-3) were used to determine SPI gel and cure characteristics (84°C), Brookfield viscosity (25°C), and a clear, unfilled 1/8" cast was prepared for heat-destruction temp. , tensile and flexural strength, flexural modulus, percent elongation, and average Barcol hardness (934-1 scale) determinations.The clear cast was prepared using a curing system of 1.0% benzoyl peroxide and 0.01% N,N- dimethylaniline at room temperature, followed by post-curing for 2 hours at 100° C. Mechanical properties of tensile (6) and flexural (6) specimens were determined using an Instron machine by standard test methods (ASTM D-638 and D- 790). Heat breakdown temperatures were determined using an Aminco plastic deflection tester (American Instrument Company) by standard test methods (ASTM D-648). The results are given in Table 1.

It will be seen that each property depended in a regular manner on the amount of VRP present in the formulation. The increases in percent elongation that resulted from the introduction of VRP were remarkable, while the reductions in heat destruction temperature, tensile strength and flexural strength were completely acceptable.

Example 2

Effect of VRP-Al on mixing styrene with

an isophthalate polyester alkyd

One part of VRP-Al was mixed with 1 or 2 parts of a commercial grade styrene-treated unsaturated isophthalic acid made from isophthalic acid, maleic anhydride and propylene glycol. The second part had no VRP added. The properties of the two materials were compared in the same way as in example 1. The results are shown in table 2.

You will see that the increase in percentage extension that stems from the introduction of approx. 7% VRP was dramatically greater and the reduction in heat destruction temperature dramatically less than for the ortho-phthalate alkyd in Example 1. This clearly shows that effective flexibilization of one type of alkyd with vinyl-terminated urethane oligomers does not make it obvious that a different type of alkyd will flexibilize effectively with the same oligomers.

Example 3

Effect of VRP-Al on mixing styrene with

an intrinsically more brittle - but also more refractory - polyester alkyd

One part of VRP-Al was mixed with 1 or 2 parts of a mixture of styrene with an unsaturated polyester alkyd, commercial grade, prepared from chloric anhydride, maleic anhydride and propoxylated neopentyl glycol. The properties of the two materials were compared in the same way as in example 1. The results are shown in table 3.

You will see that an approx. A 10 percent increase in percent elongation was achieved at the expense of a significant reduction in heat distortion temperature (HDT). However, the HDT of the non-flexibilized resin was high enough to begin with that the HDT after flexibilization was still acceptable for all practical applications of polyester resins.

Example 4

Effects of VRP-Al on the impact strength of

the alkyd/styrene mixtures from examples 1 to 3.

Ten 6.35 x 1.27 x 0.16 cm test pieces were prepared from castings of each of the formulations (mixtures) compared in Tables 1 through 3. Izod impact strength without notching was measured from the test pieces by ASTM Test Method D-256 at using a TMI impact tester no. 43-1. The results are given in table 4.

It will again be seen that the beneficial effect of VRP (on the impact strength) is far greater for the isophthalate resin from example 2 than for the orthophthalate resin from example 1. The reason for the obviously unfavorable effect on the resin from example 3 is not known-

Example 5

Effects of 2.5, 5.0 and 7.5 wt% VRPs A3- 6

on mechanical properties of an orthophthalic casting resin.

Portions of a styrene-treated, commercial grade, unsaturated orthophthalic polyester casting resin prepared by reacting phthalic anhydride (14.3 mol%), maleic anhydride (33.3 mol%) and propylene glycol (52.4 mol%) were formulated to contain 2.5, 5.0 and 7.5% by weight of each of the VRPs A3-6. A further portion of resin containing no VRP was taken for comparison. The mechanical properties of the hardened mixtures were determined by the method from example 1. The results are given in table 5.

You will see that a good balance of properties occurred with a content of approx. 5% by weight of each VRP. However, dramatic improvements in tensile strength and % elongation were achieved with all VRPs at all 3 weight percents. The A3 formulations also had better flexural strength at all weight percentages and the greatest increase in flexural modulus (4.7x10 5 at 7.5 wt% A5 versus 5.5x10<5> at 0 wt%) was not intolerable.

Example 6

A portion of the styrene-treated unsaturated orthophthalic polyester molding resin, commercial, from Example 5 and the vinyl reactive plasticizer A6 were formulated to give a 95.0, 5.0% solution, respectively. This solution was used to make a 0.15875 cm clear unfilled cast and cured using the procedure of Example 1. A test piece was made from the clear unfilled cast having the following dimensions: 16.51 cm length, 1.58 75 cm width at pointed ends, chamfered to a 1.016 cm width at center. An otherwise identical test piece was produced from another part of the casting resin to which no VRP had been added. The test pieces were used for plane tension-compression exercises with imposed tension according to the methods of P.B. Bowden and J.A. Jukes, described in Journal of Material Science 3, 183 (1968) and 7, 52 (1972). The specimen cross-sectional area was 0.16129 cm 2 and the tensile load was increased by an additional 3889 kPa. The creep rate taken as flow was approx. 0.3048 cm/sec. Stretch (kP) versus compression (kP) yielded point values thus obtained were plotted. Tensile and compressive yield strength values were determined by extrapolating the plotted biaxial yield line. Toughness was calculated as the ratio of elongation in use to tensile yield strength. The results are shown in table 6.

Example 7

Effect of 5 wt% VRP B3 on mechanical

properties of casting resin used in example 5

Portions of the casting resin containing 0' and 5% by weight VRP B3 (derived from isocyanatoethyl methacrylate and polyglycol P2000) were cured and their physical properties determined as in Example 1. The results are given in Table 7.

It will be seen that excellent flexibilization is achieved at the cost of fairly small reductions in HDT and bending properties.

Example 8

Effect of 7.5 wt% VRP-D on physical and mechanical properties of isophthalic resin used in Example 2

Portions of the styrene-treated isophthalic polyester were formulated containing 0 and 7.5 wt% VRP-D. The physical and mechanical properties of the two materials listed in Table 8 were determined as in Example 1, and the simple stress data given in Table 9 were determined as in Example 6, except that the toughness was calculated as one minus the ratio of compression at break to the pressure-yield limit.

The Izod impact strength (unnotched) of the cured 7.5% VRP-D formulation was 240 joules/met. compared to 155 for an otherwise identical portion of the styrene-treated isophthalate resin which contained no VRP (same as given for "Example 2" in Table 4.

It will be seen that the VRP flexibilized the isophthalate/styrene mixture effectively without reducing the HDT to an intolerable degree.

Claims (19)

1. Flexibilizer/alkyd mixture that does not phase-separate upon extensive curing a. an unsaturated polyester and/or polyester amidalkyd which does not contain any terminal polycycloalkenyl groups, and b. from 1 to 20 parts by weight of a flexibilizing agent comprising one or more urethane oligomers per 100 parts of the alkyd, which oligomers each have at least one vinyl-reactive end group and are an addition product of a polyether glycol with an unsaturated isocyanate or with a diisocyanate and an unsaturated compound comprising a -NC0 or -C^OH group, c. from 0 to 400 parts by weight of a non-resinous vinyl monomer per 100 parts of the alkyd, with the proviso that when the alkyd comprises an unsaturated polyester, either the weight parts of the oligomers per 100 parts alkyd not exceeding ll + 9a/(a+e) , where a and e are the respective parts by weight of the polyester amide and the polyester in the mixture, or the unsaturated compound is an unsaturated isocyanate, an alkenylphenol, a hydroxyalkyl acrylate-initiated polyglycol or N-methylolacrylamide. 2. Mixture according to claim 1, characterized in that the alkyd is the unsaturated polyesteramide and the unsaturated compound is a hydroxyalkyl acrylate, an unsaturated isocyanate, an alkenylphenol, a hydroxyalkyl acrylate-initiated polyglycol or N-methylolacrylamide. 3. Mixture according to claim 1, characterized in that the alkyd is an unsaturated isophthalic acid polyester. 4. Mixture according to claim 1, 2 or 3, characterized in that the flexibilizer comprises an addition product of the polyether glycol selected with a) an isocyanatoethyl methacrylate alone or together with a diisocyanate, b) a diisocyanate and a hydroxyalkyl acrylate-initiated polyglycol, c) a diisocyanate and p-isopropenylphenol or d) a diisocyanate and N-methylolacrylamide. 5. Mixture according to claim 1, 2 or 3, characterized in that the flexibilizer comprises an addition product of the polyether glycol with a diisocyanate and a hydroxyalkyl acrylate-initiated polyglycol, an unsaturated isocyanate-p-iso-proponylphenol or N-methylolacrylamide; in that the vinyl monomer is styrene and is present in an amount of from 60 to 70 parts by weight per 100 parts of the alkyd. 6. Mixture according to any one of the preceding claims, characterized in that the non-resin vinyl monomer is present in an amount of from 50 to 80 parts by weight per 100 parts of the alkyd. 7. Mixture according to claim 6, characterized in that the monomer is styrene and is present in an amount of from 60 to 70 parts by weight per 100 parts of the alkyd. 8. Mixture according to claims 1 to 4, characterized in that the polyether glycol is a polypropylene glycol with a molecular weight from 2000 to 3000. 9. Mixture according to claim 8, characterized in that the diisocyanate is tolylene diisocyanate. 10. Mixture according to claim 9, characterized in that the oligomer is the reaction product ay polypropylene glycol, tolylene diisocyanate and 2-hydroxypropyl acrylate. 11. Mixture according to claim 10, characterized in that the oligomer has the statistical structure 12. Mixture according to claim 5, characterized in that the oligomer has the statistical structure 13. Mixture according to claim 10, characterized in that the oligomer has the statistical structure 14. Process for the production of a flexible alkyd resin which does not phase separate by Wherding, by mixing together a. an alkyd comprising an unsaturated polyester and/or polyesteramide containing no terminal polycycloalkenyl groups, and b. from 1 to 20 parts by weight of a flexibilizing agent comprising one or more urethane oligomers per 100 parts of the alkyd, which oligomers each have at least one vinyl-reactive end group and are an addition product of a polyether glycol with an unsaturated isocyanate or with a diisocyanate or an unsaturated compound comprising a -NCO- or -Cr^ OH group, and c. from 0 to 400 parts by weight of a non-resin vinyl monomer per 100 parts of the alkyd, with the proviso that when the alkyd comprises an unsaturated polyester, either the weight parts of the oligomers per 100 parts of the alkyd not exceeding ll+9a/(a+e), where a and e are respectively the parts by weight of the polyester amide and the polyester in the mixture, or the unsaturated compound is an unsaturated isocyanate, an alkenylphenol, a hydroxyalkyl acrylate initiated polyglycol or N-methylol acrylamide. 15. Method according to claim 14, characterized in that the amount of the non-resin vinyl monomer mixed with the alkyd and/or oligomer(s) is from 50 to 80 parts by weight per 100 parts of the alkyd. 16. Method according to claim 14 or 15, characterized in that the alkyd is an isophthalic acid polyester and the monomer is styrene. 17. Method according to claim 14, characterized in that the polyglycol residue originates from a triol and the number of end groups in the oligomer is 3. 18. Method according to each of claims 14 to 17, including the step of curing the resulting mixture. 19. Cured product produced by the method according to claim 18.