RESIN COMPOSITION AND MATERIALS CONTAINING A RESIN COMPOSITION

Abstract

This invention relates to a resin composition. The resin composition comprises a first polyfunctional epoxy component (i) comprising an epoxy resin based on a alkylol alkane triglycidyl ether monomer, and a second component, (ii) comprising an epoxy resin. The composition further comprise a third component, (iii) comprising a hydrazide based curative in combination with either (a) a urone based curative or (b) an imidazole based curative or both.

Claims

1. A resin composition comprising a. a first polyfunctional epoxy component (i) comprising an epoxy resin based on an alkylol alkane triglycidyl ether monomer, and b. a second component (ii) comprising an epoxy resin, the composition further comprising c. a third component (iii) comprising a hydrazide based curative in combination with either (a) a urone based curative or (b) an imidazole based curative or both.

2. The resin composition according to claim 1, wherein the alkylol alkene triglycidylether monomer is a trialkylol alkene triglycidylether monomer.

3. The resin composition according to claim 1, wherein the alkylol alkene triglycidylether monomer is selected from the group of monomers consisting of trimethylolethane triglycidyl ether, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, p-aminophenol triglycidyl ether, 1,2,6-hexanetriol triglycidyl ether, glycerol triglycidyl ether, diglycerol triglycidyl ether, glycerol ethoxylate triglycidyl ether, castor oil triglycidyl ether, propoxylated glycerine triglycidyl ether, and/or combinations thereof.

4. The resin composition according to claim 1, wherein component (i) is based on at least two alkylol alkane triglycidyl ether monomers each having a different structure.

5. The resin composition according to claim 4, wherein component (i) comprises an epoxy novolac resin and a phenol novolac epoxy resin which differs in structure from the epoxy novolac resin.

6. The resin composition according to claim 1, wherein component (ii) is selected from a cycloaliphatic epoxy resin, a bisphenol-A epoxy resin, or a further novolac epoxy resin.

7. The resin composition according to claim 1, wherein component (ii) comprises a multifunctional epoxy resin derived from polyaddition of a dicyclopentadiene component and phenol component.

8. The composition according to claim 1, wherein the composition further comprises a component (iv) comprising at least one difunctional epoxy resin.

9. The composition according to claim 1, wherein the composition further comprises a component (v) comprising an impact modifier.

10. The composition according to claim 1, wherein the composition comprising a component (vi) comprising a filler.

11. The composition according to claim 1, wherein the average epoxy equivalent weight range of component (i) is in the range of from 150 to 200.

12. The composition according to claim 1, wherein the mixture of epoxy functional components (i) and (ii) comprises an average epoxy equivalent weight stoichiometric ratio of i) to ii) of from from 1.022 to 1.13.

13. The composition according to claim 1, wherein the composition comprises the first component (i) in the range of from 12 to 25% by weight based on the total weight of the composition.

14. The composition according to claim 1, wherein the composition comprises the second component (i) in the range of from 8 to 10% by weight based on the total weight of the composition.

15. The composition according to claim 8, wherein the composition comprises one or more difunctional epoxy resin components in the range of from 20 to 55% by weight based on the total weight of the composition.

16. The composition according to claim 1, wherein the component (iii) is in the range of from 12 to 20% by weight based on the total weight of the composition.

17. The composition according to claim 1, wherein the hydrazide based curative is a dihydrazide curative and wherein the urone based curative (a) is selected from phenyl ureas.

18. The composition according to claim 17, wherein the urone based curative is selected from 1,3-diphenylurea, benzylurea, 1,1-dimethyl-3-phenylurea, N-ethylurea, N-(2-Chloro-4-pyridyl)-N-phenylurea, N,N-dibenzylurea, N-(4-chlorophenyl) N,N-dimethyl urea, N-(4-chlorophenyl) n, n-Dimethyl urea, N-phenyl-N,N-dimethylurea, 2,4 toluene bis dimethyl urea, 2,6 toluene bis dimethyl urea, cycloaliphatic bisurea, toluene bis dimethyl urea, 4,4 methylene bis (phenyl dimethyl urea), N,N-dimethyl-N-[3-(trifluoromethyl)phenyl]-urea, 3 -(3,4-dichlorophenyl)-1,1-dimethylurea and/or combinations of the aforesaid ureas.

19. The moulding material comprising the resin matrix of claim 1, and a fibrous reinforcement material.

20. (canceled)

Description

SPECIFIC DESCRIPTION

[0043] The resin composition as described herein contains a number of epoxy resins comprising a dicyclopentadiene based epoxy resin, epoxy novolacs and a combination of a dihydrazide curative and a urone based curative. Preferably, the urone based curative comprises an aryl urea or an alkyl-aryl urea; and more preferably, the urone based curative comprises a phenyl urea.

[0044] The composition is capable of fast curing whilst the Tg, retained Tg and mechanical properties enable use of this in Industrial structural applications particularly automotive structural applications.

[0045] The resin composition preferably comprises a first polyfunctional epoxy component (i) comprising an epoxy resin based on a alkylol alkane triglycidyl ether monomer, a second component (ii) comprising an epoxy resin, and a third component (iii) comprising a hydrazide based curative in combination with a urone based curative.

[0046] Alkylol Alkene Triglycidylether Monomers

[0047] The alkylol alkene triglycidylether monomer is selected from the group of monomers consisting of trimethylolethane triglycidyl ether, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triphenylolmethane triglycidyl ether, trisphenol triglycidyl ether, tetraphenylol ethane triglycidyl ether, p-aminophenol triglycidyl ether, 1,2,6-hexanetriol triglycidyl ether, glycerol triglycidyl ether, diglycerol triglycidyl ether, glycerol ethoxylate triglycidyl ether, castor oil triglycidyl ether, propoxylated glycerine triglycidyl ether. In a preferred embodiment, the alkylol alkene triglycidylether monomer comprises an epoxy novolac resin and a phenol novolac epoxy resin which differs in structure from the epoxy novolac resin.

[0048] Curatives

[0049] The urone based curative may be selected from 1,3-diphenylurea, benzylurea, 1,1-dimethyl-3-phenylurea, N-ethylurea, N-(2-Chloro-4-pyridyl)-N-phenylurea, N,N-dibenzylurea, N-(4-chlorophenyl) N,N-dimethyl urea, N-(4-chlorophenyl) n,n-Dimethyl urea, N-phenyl-N,N-dimethylurea, 2,4 toluene bis dimethyl urea, 2,4 toluene bis dimethyl urea, cycloaliphatic bisurea, toluene bis dimethyl urea, 4,4 methylene bis (phenyl dimethyl urea), N,N-dimethyl-N-[3-(trifluoromethyl)phenyl]-urea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and/or combinations of the aforesaid ureas. In a preferred embodiment, the urone based curative is 1,1-dimethyl-3-phenylurea.

[0050] The imidazole based curative may be selected from the group consisting of compounds represented by formula (I):

##STR00001## [0051] in which R1 represents a hydrogen atom, a C1-C10 alkyl group, an aryl group, an arylalkyl group, or a cyanoethyl group, and R2 to R4 represent a hydrogen atom, a nitro group, a halogen atom, a C1-C20 alkyl group, a C1-C20 alkyl group substituted with a hydroxy group, an aryl group, an arylalkyl group, ora C1-C20 acyl group; and a part with a dashed line represents a single bond or a double bond.

[0052] The curative may be selected from one or more of the following imidazoles including 2-ethyl-4-methylimidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole, 2-undecylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, and 2-phenyl-4,5-dihydroxymethylimidazole, and imidazole, 2-ethyl-4-methylimidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole, 2-undecylimidazole, 1,2-dimethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, imidazolines including 2-methylimidazoline, 2-phenylimidazoline, 2-undecylimidazoline, 2-heptadecylimidazoline, 2-ethylimidazoline, 2-isopropylimidazoline, 2,4-dimethylimidazoline, and 2-phenyl-4-methylimidazoline, and 2-methylimidazoline or 2-phenylimidazoline, 1-isopropyl-2-methyl imidazole, 1-(2-hydroxypropyl)-2-methylimidazole, isopropyl-2-aryl imidazole, 1-isopropyl-2-aryl imidazoline and/or combinations of the aforesaid imidazoles.

[0053] The hydrazide based curative may be a dihydrazide having the following chemical structure:

##STR00002##

[0054] Wherein R comprises (CH.sub.2).sub.n or (Ar); wherein n is a number from 0 to 10; and wherein Ar is an aromatic ring.

[0055] Preferably, the hydrazide curative comprises at least one compound selected from the group consisting of: an aromatic hydrazide, an aliphatic hydrazide, and any combination thereof.

[0056] The hydrazide curative may be selected from the group consisting of: adipic dihydrazide, adipic acid dihydrazide, 3, 4-diaminobenzhydrazide, succinic dihydrazide, 4-aminobenzoic hydrazide, (+)-biotinamidohexanoic acid hydrazide, oxalyldihydrazide, maleic hydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, 1,4-cyclohexyl dihydrazide, 4,4-(propane-1,3-diylbisoxy) dibenzoic dihydrazide, terephthalic acid dihydrazide, isophthalic dihydrazide, and/or any combination thereof.

[0057] Various additives may be included in the composition.

[0058] Impact Modifiers

[0059] The composition may comprise an impact modifier. Impact modifiers are widely used to improve the impact strength for epoxy resin compositions with the aim to compensate their inherent brittleness and crack propagation. Impact modifiers may comprise rubber particles such as CTBN rubbers (carboxyl-terminated butadiene-acrylonitrile) or core shell particles which contain a rubber or other elastomeric compound encased in a polymer shell. The advantage of core shell particles over rubber particles is that they have a controlled particle size of the rubber core for effective toughening and the grafted polymer shell ensures adhesion and compatibility with the epoxy resin composition. Examples of such core shell rubbers are disclosed in EP0985692 and in WO 2014062531.

[0060] Alternative impact modifiers may include methylacrylate based polymers, polyamides, acrylics, polyacrylates, acrylate copolymers, and polyethersulphones.

[0061] Fillers

[0062] In addition the composition may comprise one or more fillers to enhance the flow properties of the composition. Suitable fillers may comprise talc, microballoons, flock, glass beads, silica, fumed silica, carbon black, fibers, filaments and recycled derivatives, and titanium dioxide.

[0063] Importantly, and preferably, a phenoxy polymer component is absent in the composition of the present invention. We have found that the absence of a phenoxy polymer component results in the achievement of the desired E Tg, E Tg (for both dry and hot wet treated samples) whilst also providing a composition with advantageous fast cure properties when cured at temperatures of over 120 C., preferably at 170 C. This renders the composition of the present invention particularly suitable for applications in compression moulding and for high volume production of compression moulded parts.

[0064] To measure the degree of cure using Digital Scanning Calorimetry the heat released during the curing reaction is related to the total heat for fully curing. This can be measured as follows. A reference resin composition sample is heated from 10 C. to 250 C. at 10 C./min rate to full cure (100%) and the generated heat Hi is recorded. The degree of cure of a particular resin sample of the same composition as the reference resin composition sample can then be measured by curing the composition sample to the desired temperature and at the desired rate and for the desired time by heating the sample at these conditions and measuring the heat He generated by this cure reaction. The degree of cure (Cure %) is then defined by:

Cure %=[(HIHe)/Hi]100 [%](-)

[0065] where Hi is the heat generated by the uncured resin heated from 10 C. up to fully cured at 250 C. and He is the heat generated by the certain degree cured resin heated up to a desired temperature and rate.

[0066] The glass transition temperature for a dry Tg and a hot wet Tg can be derived from both the storage modulus and the loss modulus using dynamic mechanical analysis.

[0067] In dynamic mechanical analysis (DMA) a resin composition sample being probed is subjected to a time-varying deformation and the sample response is measured. In the DMA experiment, a sinusoidal time-varying strain (controlled deformation) is applied to the sample:

=.sub.o sin(t) (i)

[0068] Where is the applied strain, o is the strain amplitude and is the frequency.

[0069] The DMA instrument measures the resultant stress:

=.sub.o sin(t+) (ii)

[0070] Where is the resultant stress, o is the stress amplitude and is the phase angle.

[0071] For most resin compositions due to the viscoelastic nature (both viscous component and an elastic component) there is a phase lag due to the contribution of the viscous component called the phase angle. The phase angle is important since it is used to calculate the dynamic moduli.

[0072] For small strain amplitudes and time independent polymers (linear viscoelastic regime) the resulting stress can be written in terms of the (dynamic) storage modulus (E) and the (dynamic) loss modulus (E):

=.sub.o[E sin(t)=E cos(t)](iii)

[0073] The storage modulus (E) and the loss modulus (E) can thus be calculated using the following equations derived from (iii):

[00001]$\begin{array}{cc}{E}^{}=\frac{{}_0}{{}_0}.Math.\cos .Math..Math..Math..Math.E^{}=\frac{{}_0}{{}_0}.Math.\sin .Math..Math.& \left(\mathrm{iv}\right)\end{array}$

[0074] A typical DMA experiment is to measure E and E as a function of temperature using a precise temperature-controlled oven with a linear heating ramp to the desired end temperature. Typical heating rates are in the range of 2 to 5 C./minute.

[0075] A standard test for assigning the glass transition temperature Tg by DMA is found in ASTM E1640 and is derived from the storage modulus, the loss modulus and from tan which is the ratio of the loss and storage moduli:

[00002]$\begin{array}{cc}\tan .Math.=\frac{E^{}}{E^{}}& \left(v\right)\end{array}$

[0076] From the respective moduli and tan diagrams derived by DMA, different glass transition temperatures associated with the storage modulus (E Tg), the loss modulus (E Tg) and tan (tan Tg) can be readily identified.

[0077] As defined and illustrated in ASTM standard E1640, the Tg can be labeled for a DMA resin composition sample using the following parameters:

[0078] E Tg: Occurs at the lowest temperature and is identified by the intersecting tangents corresponding to a tangent to the storage modulus curve below the transition temperature and a tangent to the storage modulus curve at the inflection point approximately midway through the sigmoidal change associated with the transitions.

[0079] E Tg: Occurs at the middle temperature and is identified as the maximum in the E curve.

[0080] Tan Delta Tg: Occurs at the highest temperature and is identified as the maximum of the tan delta curve.

EXAMPLES

[0081] Embodiments of the invention will now be described by way of example only.

[0082] The following constituent components were used in the preparation of the compositions of the Examples.

TABLE-US-00001 Component Description MY 721 triglycidyl ether based epoxy, average EEW 113 (Huntsman) Epikote 615 epoxy novolac resin, average EEW 175 (Hexion) DEN 438 novolac epoxy average EEW 180 (Olin) GT 6071 bisphenol A epoxy average EEW 457 (Huntsman) GT 7071 bisphenol A epoxy average EEW 512 (Huntsman) MX153 core shell rubber dispersed in bisphenol A DER331 of average EEW 269 (Kaneka) DW0137 carbon black filler (Dow) Epikote 828 bisphenol A epoxy, average EEW 187(Hexion) ADH adipic dihydrazide (ACCI) U52 blend of 2,4 toluene bis dimethyl urea and 2,6 toluene bis dimethyl urea (Alzchem) PDU phenyl dimethyl urea (ACCI) U500 2,4 toluene bis dimethyl urea (Alzchem) 556 cycloaliphatic epoxy resin, average EEW 252 (Huntsman) 2E4MZ 2-ethyl-4-methylimidazole (Alzchem)

[0083] In the Examples the following parameters were measured:

TABLE-US-00002 Parameter (unit) Description Speed of cure (s) ASTM D2471 Time to peak and time to 95% cure using Dielectric analysis (DEA) Tg ( C.) Glass transition temperature of cured resin matrix composition, measured from DMA in accordance with standard ASTM E1640 Wet Tg ( C.) immersion of cured resin composition in water at 70 C. for 2 week, Tg measured from DMA according to ASTM E1640 E Tg ( C.) Tg for dry and hot wet treated samples, determined in accordance with ASTM E1640 at a ramp rate of 5 C./min and derived from storage modulus E E Tg ( C.) for dry and hot wet treated samples, determined in accordance with ASTM E1640 at a ramp rate of 5 C./min from loss modulus E E retention (%) E Wet Tg/E Tg * 100 E retention (%) E Wet Tg/E Tg * 100

[0084] Various resin compositions were prepared by heating an novolac epoxy component and subsequently blending in the other epoxy resin components followed by the other constituent components of the compositions as outlined in Table 1.

[0085] The compositions for Examples 1 to 6 are set out in the below Table 1. All amounts are weight % based on the total weight of the composition for each composition of each Example.

TABLE-US-00003 TABLE 1 Compositions for the compositions of Examples 1 to 6 Example Example Example Example Example Example Component 1 2 3 4 5 6 MY 721 5.0 10.0 10.0 556 10.0 Epikote 615 22.0 22.0 22.0 10.0 20.0 19.0 YDPN638 5.0 5.0 5.0 16.5 16.5 GT6071 20.0 10.0 5.0 15.5 25.0 15.5 GT7071 5.0 10.0 MX153 20.0 20.0 20.0 19.5 12.0 19.0 Epikote828 14.0 14.0 14.0 14.5 24.0 15.5 DW0137 1.0 1.0 1.0 1.0 1.0 1.0 ADH 7.0 7.0 7.0 7.0 9.0 7.0 U52 6.0 6.0 6.0 6.0 7.0 6.0 UR500 2.0 2E4MZ 0.5

[0086] The resin compositions of Examples 1 to 6 were exposed to a temperature of 170 C. and the time to peak exotherm and the time to cure to reach 95% cure were measured. The results are shown in Table 2.

TABLE-US-00004 TABLE 2 Speed of cure at 170 C. Example Example Example Example Example Example Measurement 1 2 3 4 5 6 Time to peak 0.7 0.6 0.4 1.6 1.0 0.9 (DEA) @ 170 C. (mins) Time to 95% 1.5 1.7 1.7 4.6 1.8 2.0 DEA @ 170 C. (mins)

[0087] The Tg and wet Tg were also measured in addition to a number of additional parameters after exposing the compositions to a temperature of 170 C. for 3 minutes to cure the compositions.

TABLE-US-00005 TABLE 3 ETg and ETg (dry and wet), and E and E retention for Examples 1 to 6 Example Example Example Example Example Example Measurement 1 2 3 4 5 6 No conditioningno aging E Tg ( C.) 135 140 141 135 135 143 E Tg ( C.) 161 168 167 142 148 148 Conditioned2 weeks immersion in water at 70 C. E Tg ( C.) 100 98 102 100 100 102 E Tg ( C.) 110 110 118 E retention 74.1 70.0 72.3 74.0 74.0 71.3 (%) E retention 77.5 74.3 79.7 (%)

[0088] The resin composition of the invention can thus be cured to at least 95% of cure in under 2 minutes at 170 C. (as measured using DSC (Digital Scanning Calorimetry) or DEA (dielectric cure monitoring)) with a cured Tg of over 130 C. and a hot wet Tg of over 100 C. and can thus provide the desired mechanical properties for structural applications.