CA1112398A - Polyepoxide-polyacrylate ester compositions - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Curable compositions are made from a blend of an epoxide resin and a polyacrylate or polymethacrylate ester. Such compositions cure rapidly even at low temperatures when mixed with alphatic polyamines and are useful in coating and adhesive applications.

Description

BACKGROUND OF THE I ENTION
The ~ield of art to which this invention pertains is synthetic resins obtained by the reactlon of compounds containing more than one epoxy group with curing agents, particularly aliphatic amine curing agents.
Epoxide resins are well known compositions which have found a wide variety of uses and which have been reacted with a wide variety of curing agents to form cured compositions. Very useful curing agents are aliphatic amines~ However, in some applications, epoxide resins cured with aliphatic amines are lacking in some desirable properties. Epoxide resin/aliphatic amine systems are deficient ln low temperature cure response in that such systems do not cure satisfactorily at temperatures be~ow 40F. Also, such systems, especially at low temperatures, are viscous and do not properly wet the substrate to which they are applied. In addition coatings made from epoxide resin/aliphatic amine curable composltions, when cured at room temperature under atmospheric conditions, often have greasy uneven surfaces. Finally7 such systems, particularly in large masses, will undergo exothermic reactions which are difficult to control.
U.S. patent 3,383,434 discloses a curable system made from a diepoxide resin, an unsaturated polyester and a polyamine which has two primary amine groups. According to the patent, the disclosed system will react rapidly at low temperatures to give thermoset resins. The amine reacts with the C - C
bond contained in the polyester as well as with the epoxy groups to form a com-plex cross-linked resin. Such syste~s are said to have short gel times and low peak exotherms. However, such systems are viscous and exhibit poor wetting properties.
U.S. patent 2,g48,447 describes cold-setting adhesives made from epoxide resins diluted with a cyano-substituted hydrocarbon cured with a polyamine~
Acetonitrile is the preferred diluent although acrylonitrile and methacryloni-.

,. , ~

:
, f~ 23~

trlle are disclosed as being useful. ~crylonitrile and methacrylonitrile are monoEunctional and volatile.
U.S. patent 2,939,859 discloses curable compositions ~ade from a poly~
epoxide resin, styrene and an epoxide resin curing agent plus, pre~erably, a peroxide catalyst. Styrene i9 mono~unctional and volatile.
SUMMARY OF T~IE IN~ENTION
This invention pertains to curable epoxide resin compositions. In par-ticular this invention relates to epoxide resins cured with aliphatic poly-amines. More particularly, this invention relates to epoxide resin/poly-acrylate ester or polymethacrylate ester compositions.
The curable composition of this invention is a blend of an epoxide resin, which contains more than one 1,2 epoxy group per molecule, and a poly-acrylate or polymethacrylate ester of a polyol wherein said ester contains more than one terminal acrylate or methacry]ate group, the epoxide resin and the ester being present in the weight ratio o~ about 100 parts of epoxide resin to about 5 to about 100 parts of ester. The epoxide resin/polyacrylate or poly-methacrylate blend is cured wlth an aliphatic polyamine containing at least 3 amine hydrogen atoms per molecule in the amount of about 0.75 to about 1.25 amine hydrogen atoms or each epoxy group and each acrylic unsaturated group.
The curable compositions of this invention when reacted with aliphatic polyamines will cure even in thin films at temperatures as low as 32F. The composltions exhibit low exotherm temperatures. When drawn down as coatings, the compositions are less prone to form 'sweatout than similar coatings based on epoxide resir,s which do not contain the polyacrylate ester modification.
The compositions of this invention have low viscosities and their excellent !~
~etting characteristics are rea~ily apparent, as evidenced by high bond strength, when applied in bondline thinknesses to metal, plastic, damp concrete and other difficult to wet subs-trates.

,~ ~
,,~

DESCRIPTION OF THE I~V~TION
The epoxide resins useful in this invention are those resins which con tain more than one 1,2-epoxy group per molecule. They can be saturated or un saturated, aliphatic, cycloaliphatic or heterocyclic and can be monomeric or polymeric in nature. The weights per epoxide of such resins will be wLthin the range of about 100 to about 2,000. Preferably, the epoxide resins will contain glycidyl ether or ester groups, will be liquid rather than solid and will have weights per epoxide in the range of about 110 to about 500, most preferably about 175 to about 250.
Useful epoxide resins are glycidyl polyethers of polyhydric phenols which are derived from an epihalohydrin, e.g., epichlorohydrinl and a poly-hydric phenol. Examples of such polyhydric phenols include resorcinol, hy-droquinone, bis(4-hydroxyphenyl)-2,2-propane, or bisphenol A as it is commonly called, 4,4'-dihydroxybenzophenone, bis(4-hydroxyphenyl~ ethane, bis(~-hy-droxyphenyl)-1,1-isobutane, bis(~ hydroxyphenyl)2,2-butane, bis(2-dihydroxy-naphthyl)~ethane, phloroglucinol, and bis(4-hydroxyphenyl)sulfone. Additional polyhydric phenols are novolac resins containing more than two phenol, or sub-stituted phenol, moieties linked through methylene bridges as well as halo-genated, e.g., brominated and chlorinated, phenolic co~pounds.
Additional epoxide resins are glycidyl polyethers of polyhydric alcohols prepared by reacting a polyhydric alcohol with an epihalohydrin using an acidic catalystS e.g., boron trifluoride, and subsequently treating the resulting f product wlth an alkaline dehydrohalogenating agent. Included among the poly-hydric alcohols that can be used in the preparation of these polyepoxides are glycerine, ethylene glycol, propylene glycol, diethylene glycol~ hexanediol, f hexanetriol~ trimethylol propane, trimethylol ethane, pentaerythritol and the ~
like~ a Epoxide resins and their preparations are described in ~.S.

f ... ~.. , .. . , , ~ , , .
.
.: ~. ' ' .:
.
, .
- ::

patents 2,467,171, 2,615,007, 2,615,008, 2,801,227, 2,538,072 and 3,033,803.
Other epo~ide resins are glyc:idyl esters ol po.LycarboxylLc acids whicl are derived from an epihalohydrin and a polycarboxy:li.c acid using procedures described in V.S. patent 3,859,31~ and 3,576,827 which are herein incorporated by reference. Examples of polycarboxylic acids :include phthalic acld or its anhydride, isophthalic acid, terephthalic acid, ~etrahydrophthalic ~cid, hexahydrophthalic anhydride, adipic acid, dimerized fatty acids, dibasic acids made from an unsaturated fatty acid and acrylic acid and acrylic acid and the like.
O The most preferred epoxide resins are glycidyl polyethers of polyhydric phenols, particularly the glycidyl polyether of bisphenol A.
The polyacrylate and polymethacrylate ester of polyols useful in this invention are those esters which contain more than one tennin.al acrylate or methacrylate group. These esters are the acrylic and methacrylic acid esters of aliphatic polyhydric alcohols such as, for example~ the di- and poly-acrylates and the di- and polymethacrylates of alkylene glycols, alkoxylene glycols, alicyctic glycols and higher polyols, such as ethylene glycol, tri-ethylene glycol, tetraethylene glycol, tetramethylene glycol, hexanediol, tri-methylolethane, trimethylolpropane, pentaerythritol, dip~ntaerythritol, tri-:0 pentaerythritol and the like, or mixtures of these with each other or with thelr partially esterified analogs.
Typical compounds include but are not limited to trimethylolpropane tri-acrylate, trimethylolethane triacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylene glycol dimethacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, penta-erythritol triacrylate, pentaerythritol tetraacrylate, 1,6-hexanediol di-acrylate, 1,6-hexanediol dimethacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, and the like. Particularly preferred esters are 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, and pentaerythriLol tetraacrylate.
Additional acrylate or methacrylate es~ers of polyols are the acrylate or methacrylate esters of epoxide resins, wherein epoxide resins are used here-in are considered to be polyols. The epoxide resins useful in reacting with acrylic or methacrylic acid are those epoxide resins described hereinbefore.
The procedures for preparing these acrylate and methacrylate esters of epoxide resins is described in U.S. patent 3,377,~06.
The acrylate or methacrylate esters of the polyols are blended wlth the epoxide resins in the weight ratio of about 5 to about 100 parts oi ester for each 100 parts of epoxide resin.
The preferred curing agents for the compositions of this invention are aliphatic polyamines having at least 3 active amine hydrogen atoms per mole-culeO Examples of such amines are the polyalkylene polyamines, e.g., di-ethylene/triamine, triethylene/tetraamine, tetraethylene/pentamine and penta-ethylene/hexamine. Additional useful a~ines are ethylene diamine, tetra-methylene diamine, hexamethylene diamine, xylylene diamine, and the like.
Adducts of such amines with acrylonitrile, acrylic acid, ethyl acrylate and the like are also useful if the adduct contains at least three active amine hydro-gen atoms. Also included as useEul amines are amidoamines obtained by reacting polyamines with fatty aclds, both monomers and dimers, provided of course that the resulting amidoamine contains at least 3 active amine hydrogen atoms per molecule~ i ~dditional curing agents which can be used with the compositions of this invention include aromatic aminesS mercaptans and anhydrides although generally soft, low strength thermoset resins are obtainedO
The polyamine is utilized with the polyepoxide resin/polyacrylate or poly~ethacrylate blend in approximate equivalent ratios, i.e., about 0.75 Lo .;,1 : :: ' ' ' ,:
., ', . ~ .

about 1.25 amine hydrogen equivalents for each epoxy group in the epoxide resin and each acrylic unsaturated group in the ester~ T~le amlne groups react wi~h the epoxide groups opening the epo~ide ring to ~orm a substituted amine group and a hydroxyl group. The an1ine groups add across the double bond of tlle acrylate group through Michael addition to form subs~Ltuted amine groups and a saturated carbon to carbon linkages.
The compositions of the instant invention can be compounded with various fillers9 reinforcing agents, dies, pigments and other additives depending upon the end use and desired properties. The co~lpositions can be dissolved in and used from solvents, e.g., aromatic hydrocarbons, ethers, ether~esters, ether~
alcohols, esters, alcohols, ketones and the like. tlowever, because of their low viscosity, these compositions are particularly adaptable to being used with no solvents, i.e., at 100% solids.
The compositions of this invention find utility wherever epoxide resins are generally used, i.e., as coatings, adhesives, castings, moldings, encap-; sulations and the like. Of particular interest are uses of the composltions at ; temperatures below 50F., down to about 32F. Specific applications for these compositions are rapid set adhesives and patching compounds capable of satis-factory use at application temperatures of 32F., two-component spray applied traffic striping, wear resistant surfacing and clear sealers, In the following examples, all parts and percentages are parts and per-centages by weight unless otherwise specified.
Example 1 To 60 parts of the diglycidyl ether of bisphenol A having an epoxide ~.
equivalent weight o 190 and a viscosity of 12,000 cps. at 25C. were blended 40 parts 1,6-hexanediol diacrylate. The resulting blend had a viscosity at 25C~ of 100 cps., a weight per gallon of 9.19 lbs. and a Gardner color of 1. 1-' To the blend (100 parts) were added 16 parts of triethylene tetraamine. The , ~'.
- 6 - ~
~'.

~.
.. ... . .
: .: ,~ , , ' ' ~
'' ", "' , gel time after mixing Ln the curing agent for a 100 gm. mass was 13 rninutes wi~h a peak exothermic ~emperature being 17~C.
Castings were prepared from the blend of epoxide resin, polyacrylate ester and curing agent, and were cured for two weeks at 25C. The physLcal properties of the casLillgs are listed in Table I.
Example 2 To 80 parts of the diglycidyl ether oE bisphenol A described in Example 1 were blended 20 parts of 1,6-hexanediol diacrylate. The resulting blend had a viscosity of 610 cps. at ~5C. To the blend were adcled 14.3 parts of triethylene tetraamine. The gel time after mixing in the curing agent was 17 minutes for a 100 gm. mass ~rlth a peak exotherm of 182C. Castings prepared from the blend of digylcidyl ether, acrylate ester and curing agent were cured for 2 weeks at room temperature. The physical properties of the castings are listed in Table I.
Example 3 To 60 parts oE the digylcidyl ether of bisphenol A described in Example 1 were blended 40 parts of trimethylolpropane triacrylate. ~e resulting blend had a viscosity of 25C. of 900 cps., a Gardner color of 1 and a weight per gallon of 9.46 lbs. To the blend were added 17 parts of trl~
ethylene tetraamine. The gel time after mixing in the curing agent was 2.5 minutes for a 100 gm. mass with a peak exotherm of 188C. Castings, prepared from the blend were cured for 2 weeks at 25C. The physical properties of the castings are listed in Table I.
Example 4 To 80 parts of the diglycidyl ether described in ~xample 1 were added 20 parts of trimethylolpropane triacrylate. The resulting blend had a vis-cosity at 25C. of 2,~40 cps. To the blend were added 15 parts of tri-ethylene tetraamine curing agent. ~he gel time after mixing in the curing ~ 7 ~
I

' ~ ~

.. , , :
': . ' ' ' ,' ~ :

. . .
.' ~ .

~ 23'~ 1 I

agent was 4.5 minutes for a 100 gm. mass with a peak exotherm of 196C.
Casting prepared from the blend and curing agent were cured for 2 weeks at 25C. The physical properties of the castings are listed in Table I.
TABLE I
Physical Properties Exo 1 Ex, 2 Ex. 3 ~. 4 Tensile Strength (psi) 6,200 10,200 10,000 10,600 Elongation @ Break (%) 21 4.2 3.4 2~5 Flexural Strength (psi)9,000 16,000 15,600 17,400 Initial Fle~ural Modulas t106psi)0.29 0.50 0.50 0.56 Compressive Strength (psi) Ultimate 30,000 21,000 18,000 14,900 @ Yield 8,400 13,000 13,000 14,900 Izod Impart (Ft.Lbs./In.Notch) 0.59 1.05 0.46 0.37 Hardness, Shore D 80 84 85 85 Heat Distortion Temp. ( DC) 45 55 56 59 Weight Loss, 24 hrs. @ 150C. (%)2.68 1.11 0.38 0.33 Absorption, 24 hrs. in:
Water 0.29 0.16 0.15 0014 5% Acetic Acid in Water2.31 0.94 1.31 1.31 5% NaOH in Water 0.28 0.16 0015 0.14 Solvent(1) 1.55 0.18 0.04 0.07 Dielectric Constant(2) 3.98 4.10 3.97 4.06 Dissipation Factor(2) 0.033 0~027 0.025 0.022 Volume Resistivity (ohm-Cm) 4 6(1015) 1~9(1016) 2.4(1016) 2.7(1016) (1)50% Xylene; 50% Isopropanol

(2)De~ermined at 100 Hk and 25C.
Example 5 Castings were prepared from the epoxide resin, acrylate ester, curing agent blend described in Fxample 3. These castings were cured for lG hours at 25C. plus 2 hours at 100C. The physical properties of these castings are lifited in Table II.
Example 6 To 100 parts of the glycldyl polyether described in Example 1 were added 12 parts of triethylene tetraamine curing agent. The gel time after the addition of the curing agent was 31 minutes for a 100 gram mass with a peak exotherm of 229C. Castings prepared from the glycidyl polyether and the curing agent were cured for 16 hours at 25C, plus 2 hours at 100C. The : . . . . : : .

-, ,~

physical properties of these castings are listed in Table II.
TABLE II
Physical Properties Ex. 5 Ex. 6 Tensile Strength (psi) 8,900 12,500 Elongation @ Break (%) 4.2 5.3 Flexural Strength (psi) 15,000 20,000 Initial Flexural Modulus (106 psi) 0.41 0.51 Compressive Strength (psi) Ultimate 29,000 35,000 % Yield 11,000 16,000 Izod Impact (Ft.Lbs~/In.Notch)0.69 0.51 ~rdness, Shore D 86 87 Heat Distortion Temp. (C) 79 l01 Weight Loss, 24 hrs. @ 150C. (%) 0.21 0.16 % Absorption, 24 hrs. in:
Water 0.17 0.15 5% Acetic Acid in Water 0.57 0.19 5% NaOH in Water 0.16 0.15 Solvent(1) 0.01 0.02 Dielectric Constant(2) 3.80 4.08 Dissipation Factor(2) 0~029 0.026 Volume Resistivity (ohm-Cm)I.8(1016)1.8(1016) (1) 50% Xylene; 50% Isopropanol (2) Determined at 100 Hz and 25C.

The above examples are meant to merely be illustrative of the instant invention. Many other variations may be made on the instant invention without departing from the scope and spirit of the instant invention.

`

Claims (9)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A curable composition which comprises: (1) a blend of an epoxide resin containing more than one 1,2-epoxy group per molecule and a polyacrylate or polymethacrylate ester of a polyol wherein said ester contains more than one terminal acrylate or methacrylate group, the epoxide resin and the ester being present in the weight ratio of about 100 parts of epoxide resin to about 5 to about 100 parts of the ester; and (2) an aliphatic polyamine curing agent con taining at least 3 amine hydrogen atoms per molecule in the amount of about 0.75 to about 1.25 amine hydrogen atoms for each epoxy group of the epoxide resin and for each acrylic unsaturated group of the polyacrylate or poly-methacrylate ester, said amine atoms reacting with the epoxide ring and adding across the double bond of the acrylate group of the composition.

2. The composition of claim 1 wherein the epoxide resin is a glycidyl poly-ether of polyester having an epoxide equivalent weight of about 100 to about 2000.

3. The composition of claim 1 wherein the epoxide resin is a glycidyl poly-ether of a polyhydric phenol having an epoxide equivalent weight of about 110 to about 500.

4. The composition of claim 3 wherein the epoxide resin is a glycidyl poly-ether of bis(4-hydroxyphenyl)-2,2-propane having an epoxide equivalent weight of about 175 to about 250.

5. The composition of claim 1 wherein the polyacrylate ester is 1,6-hexanediol diacrylate.

6. The composition of claim 1 wherein the polyacrylate ester is trimethyl-olpropane triacrylate.

7. The composition of claim 1 wherein the aliphatic polyamine is a poly-alkylene polyamine.

8. The composition of claim 7 wherein the polyalkylene polyamine is tri-ethylene tetraamine.

9. The cured composition obtained from the composition of claim 1.