JP5102732B2 - Two-component reactive polyurethane resin composition and electric and electronic parts using the resin composition - Google Patents

Description

  The present invention relates to a two-component reactive polyurethane resin composition and an electric / electronic component using the resin composition. More specifically, the two-component reactive polyurethane capable of maintaining excellent heat dissipation and flexibility over a long period of time. The present invention relates to a resin composition and a polyurethane resin using the same.

  Conventionally, electronic circuit boards and electronic components have been sealed with polyurethane resin or the like in order to prevent external contamination. In recent years, as seen in LSIs and the like, the amount of heat generated on an electronic circuit board is locally increased due to the integration, miniaturization, and higher functionality of electronic circuits. Therefore, since it is necessary to release the generated heat to the outside more efficiently, the resin to be sealed is required to have high heat dissipation.

  In addition, as the life of electronic circuit boards and electronic components is extended, it is also required that the sealing material maintain heat dissipation for a long time. Therefore, even if it is a case where it is used for a long period of time, it is also required to have flexibility that can sufficiently adhere to an electronic circuit board and an electronic component.

  In view of such a point, various heat-radiating polyurethane resin compositions have been developed to solve the above problems. For example, it has been studied to impart thermal conductivity to a polyurethane resin by blending an inorganic filler with a polyol component (Patent Documents 1 to 4). However, it cannot be said that these polyurethane resins have sufficient heat dissipation.

  In order to solve this problem, it is disclosed that a polyurethane resin having excellent heat dissipation is obtained by blending an inorganic filler at a high ratio using polybutadiene polyol and castor oil transesterification as polyol (Patent Document 5). And 6). However, since these polyols all have a large amount of double bonds in the molecule, the hardness of the polyurethane resin increases with time when used under high temperature conditions. It was difficult to maintain.

On the other hand, hydrogenated polyols in which hydrogen is added to the double bonds of the polyols are known as such materials having excellent heat resistance. Polyurethane resins using this hydrogenated polyisoprene polyol are disclosed (Patent Documents 7 and 8). However, since these polyurethane resins have a low blending ratio of the inorganic filler, those having sufficient thermal conductivity have not been obtained. In general, hydrogenated polyols are known to have very high viscosity compared to polyols prior to hydrogenation, and increasing the blending ratio of inorganic fillers causes the polyol component to become paste-like, There was a problem that it could not be used.
JP 2000-226426 A JP 2002-121529 A JP 2004-300300 A JP 2004-342758 A JP 2003-138130 A JP 2007-131830 A JP-A-11-166032 JP 2003-133493 A

  The present invention has been made in view of the above prior art, and an object of the present invention is to provide a two-component reactive polyurethane resin composition capable of maintaining excellent heat dissipation and flexibility over a long period of time, and It is to provide electric and electronic parts used.

The two-component reactive polyurethane resin composition of the present invention is a two-component reactive polyurethane resin composition comprising (I) a polyol component and (II) an isocyanate component, wherein (I) the polyol component is (A) water. Containing polyisoprene polyol, (B) castor oil-based polyol, (C) phosphoric acid ester represented by general formula (1), (D) inorganic filler , (I) polyol component and (II ) If the total amount of the isocyanate component was 100 weight percent, wherein that you containing 50 to 95% by weight of (D) an inorganic filler.

Here, R is a hydrocarbon group having 1 to 30 carbon atoms, m is an integer of 0 to 20, n is an integer of 1 to 20, and R ′ is OH or a group represented by the general formula (2). In 1) and the general formula (2), R ″ is CH ₃ or CH ₂ CH ₃ , and “/” indicates that the oxyalkylene groups described on the left and right sides thereof may be block addition or random addition.

  The two-component reactive polyurethane resin composition of the present invention preferably further contains (E) a plasticizer.

  Since the polyurethane resin composition of the present invention contains the phosphate ester represented by (C) the general formula (I), the polyol component is compared even when the inorganic filler is used in a high proportion. Can be blended with low viscosity. In addition, the polyurethane resin of the present invention has excellent heat dissipation, and the resin does not melt under high temperature conditions and the change in hardness is small. A large amount of generated heat can be released to the outside by being in close contact with.

  (A) Hydrogenated polyisoprene polyol, which is one of the polyol components (I) in the two-component reactive polyurethane resin composition of the present invention, is a hydrogenated polyisoprene polyol double bond by a known method. is there.

  (A) The iodine value of hydrogenated polyisoprene polyol is preferably 0.1 to 100 g / 100 g, more preferably 0.1 to 50 g / 100 g. If the iodine value is larger than the above range, the hardness may increase with time at high temperatures, and the flexibility may decrease.

  In addition, as (B) castor oil-based polyol which is one of the polyol components (I), castor oil, castor oil fatty acid, and hydrogenated castor oil or hydrogenated castor oil fatty acid hydrogenated to these are used. Can do. Examples of such polyols include castor oil, a transesterification product of castor oil and other natural fats, a reaction product of castor oil and polyhydric alcohol, an esterification reaction product of castor oil fatty acid and polyhydric alcohol, and alkylene oxide added thereto. Examples include polymerized polyols. Especially, the viewpoint of workability | operativity being more preferable that the viscosity in 25 degreeC is 3000 mPa * s or less.

  The mixing ratio of the (A) hydrogenated polyisoprene polyol and the (B) castor oil-based polyol is preferably 90/10 to 50/50 (weight ratio). By setting it within the above range, more excellent flexibility can be obtained.

  The phosphoric acid ester represented by (C) the general formula (I) used for the (I) polyol component of the present invention is, for example, a polyalkylene having alkylene oxide added to a monoalcohol having 1 to 30 carbon atoms by a known method It can be obtained by reacting ether monool with phosphoric anhydride. In addition, the said alkylene oxide should just have ethylene oxide as an essential component, and can also use propylene oxide and butylene oxide together. Furthermore, the number of added moles of alkylene oxide and the reaction ratio between the polyether monool and phosphoric anhydride are appropriately selected so as to satisfy the condition of the general formula (1).

  The blending amount of the phosphate ester represented by the general formula (I) used in the (I) polyol component of the present invention is 100% by weight of the total amount of the (I) polyol component and the (II) isocyanate component. In this case, 0.01 to 5% by weight is preferable, and 0.1 to 3% by weight is more preferable. When the above range is exceeded, it is difficult to obtain a further viscosity-reducing effect due to an increase in the amount used, and the physical properties of the polyurethane resin also tend to be reduced, and below the above range, the addition of (C) phosphate ester is caused. There is a tendency that the thinning effect is insufficient.

  Examples of the inorganic filler (D) blended with the (I) polyol component of the present invention include alumina, aluminum hydroxide, aluminum nitride, boron nitride, magnesium hydroxide, magnesium oxide and the like. Of these, alumina, magnesium oxide, aluminum nitride, and boron nitride are preferable because of excellent heat dissipation.

  (D) The inorganic filler is preferably at least two types of mixtures having different average particle diameters. Specifically, the ratio (D1) / (D2) of the average particle size of (D1) inorganic filler having the largest average particle size and (D2) inorganic filler having the smallest average particle size is 1.5 to 100 is preferable, and 2 to 50 is more preferable. By making it within the above range, the viscosity of the polyol component can be further reduced.

  Further, the weight ratio of (D1) the inorganic filler having the largest average particle diameter and (D2) the smallest inorganic filler having the smallest average particle diameter is (D1) / (D2) = 99/1 to 50/50. Is preferred.

  (D) The blending amount of the inorganic filler is preferably 50 to 95% by weight, more preferably 60 to 95% by weight when the total amount of (I) polyol component and (II) isocyanate component is 100% by weight. 70 to 90% is more preferable. When the blending amount of the (D) inorganic filler is less than the above range, the heat dissipation effect is reduced, and when it is more than the above range, the increase in viscosity of the (I) polyol component is increased.

  As the (II) polyisocyanate component in the two-component reactive polyurethane resin composition of the present invention, tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4- Aliphatic polyisocyanates such as trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′- Dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis (isocyanate methyl) cyclo Cycloaliphatic polyisocyanates such as xanthol, tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 4,4′-dibenzyldiisocyanate, 1 , 5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, aromatic polyisocyanate such as 1,4-phenylene diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, α, α, α, α-tetramethyl Changes in aromatic aliphatic polyisocyanates such as xylylene diisocyanate and their carbodiimides, isocyanurates, burettes, adducts, etc. It can be used polyisocyanate compound body or the like.

  In addition, an isocyanate group-terminated urethane prepolymer obtained by reacting the polyisocyanate compound with (A) a hydrogenated polyisoprene polyol and / or (B) a castor oil-based polyol can also be used as the (II) polyisocyanate component. . These (II) polyisocyanate components may be used alone or in combination of two or more.

  In the polyurethane resin composition of the present invention, the molar ratio (NCO) of (II) the isocyanate group contained in the polyisocyanate component and the sum of the hydroxyl groups contained in (A) hydrogenated polyisoprene polyol and (B) castor oil-based polyol. / OH) is preferably 1.0 to 2.0. This is because if the molar ratio of the isocyanate group to the hydroxyl group is smaller than this range, the resulting resin has low heat resistance, and if it is larger than this range, the resin becomes hard and the flexibility may be poor.

  A plasticizer can be further added to either or both of the (I) polyol component and (II) polyisocyanate component of the present invention. Examples of such plasticizers include phthalates such as dioctyl phthalate, diisononyl phthalate, and diundecyl phthalate, adipates such as dioctyl adipate and diisononyl adipate, methyl acetyl ricinolate, butyl acetyl ricinoleate, acetylated ricinoleate triglyceride Examples include castor oil-based esters such as acetylated polyricinoleic acid triglyceride, and phosphate triesters such as tricresyl phosphate and trixylenyl phosphate.

  The blending amount of the plasticizer is preferably 0.5 to 15% by weight and more preferably 1 to 10% by weight when the two-component reactive polyurethane resin composition is 100% by weight. When the amount is less than 0.5% by weight, the sufficient viscosity reducing effect of the polyol component and the flexibility of the polyurethane resin tend to be difficult to obtain. When the amount is more than 15% by weight, various physical properties such as the strength of the polyurethane resin are present. It tends to decrease.

  Various additives such as a catalyst, an antioxidant, a hygroscopic agent, an antifungal agent, and a silane coupling agent can be added to the two-component reactive polyurethane resin composition of the present invention as necessary.

  The polyurethane resin obtained by curing the polyurethane resin composition of the present invention preferably has a hardness of 50 or less according to Type D at 25 ° C. The polyurethane resin preferably has a hardness of 50 or less after standing at 150 ° C. for 300 hours and then standing at 25 ° C. for 24 hours. Furthermore, the thermal conductivity of the polyurethane resin is preferably in the range of 1 to 4 W / m · K.

  Since the polyurethane resin of the present invention has high heat dissipation and can maintain flexibility over a long period of time, it can be suitably used for electrical and electronic parts that generate heat. Examples of such electric and electronic parts include electric washing machines, toilet seats, water heaters, water purifiers, baths, dishwashers, electric tools, automobiles, motorbikes, coils, and device control bases.

  Hereinafter, based on an Example and a comparative example, the heat dissipation polyurethane resin composition and heat dissipation polyurethane sheet of this invention are demonstrated in detail. In the present specification, “parts” and “%” represent “parts by weight” and “% by weight”, respectively, unless otherwise specified.

  Table 1 shows raw materials (excluding the component (C)) used in the following Examples and Comparative Examples. (C) The phosphate ester component was synthesized as follows.

(C-1: Synthesis of phosphate ester 1)
Using lauryl alcohol as a starting material, 2 mol of propylene oxide and 8 mol of ethylene oxide were block-added by a known method to obtain an alkylene oxide adduct of lauryl alcohol.

  Subsequently, 300 g of the above alkylene oxide adduct of lauryl alcohol and 27.1 g of phosphoric anhydride were charged in a four-necked flask at a molar ratio of 2.4: 1 and reacted at 70 ° C. for 4 hours with stirring. To obtain phosphoric acid ester 1 (theoretical substitution number 1.2 of OH group of phosphoric acid).

(C-2: Synthesis of phosphate ester 2)
Tridecyl alcohol was used as a starting material, and 10 mol of ethylene oxide was added by a known method to obtain an alkylene oxide adduct A of tridecyl alcohol.

  Subsequently, 300 g of the above tridecyl alcohol alkylene oxide adduct A and 22.2 g of phosphoric anhydride were charged in a four-necked flask at a molar ratio of 3: 1 and stirred at 70 ° C. for 4 hours. Reaction was carried out to obtain phosphoric acid ester 2 (theoretical substitution number 1.5 of OH group of phosphoric acid).

(C-3: Synthesis of phosphate ester 3)
Tridecyl alcohol was used as a starting material, and 7 mol of ethylene oxide was added using a known method to obtain an alkylene oxide adduct B of tridecyl alcohol.

  Subsequently, 300 g of the above-mentioned alkylene oxide adduct B of tridecyl alcohol and 23.3 g of phosphoric anhydride were charged in a four-necked flask at a molar ratio of 3.6: 1 at 70 ° C. with stirring. Reaction was performed for 4 hours to obtain phosphoric ester 3 (theoretical substitution number of phosphoric acid OH group 1.8).

<Examples 1-8 and Comparative Examples 1-3>
The polyurethane resin compositions of each Example and each Comparative Example were prepared according to the formulation shown in Table 2. In the preparation, among the components shown in Table 2, components other than (II) polyisocyanate component were mixed under reduced pressure, and (II) polyisocyanate component was added to this mixture, whereby each example and each comparative example were A polyurethane resin composition was obtained.

<Evaluation test>
A test piece of polyurethane resin was prepared using the polyurethane resin composition, and an evaluation test was performed. The polyurethane resin test piece was prepared by pouring the polyurethane resin composition into a 6 cm × 12 cm × 1 cm mold, curing at 80 ° C. for 16 hours, and then removing the mold.

  About the test piece of each Example and each comparative example obtained above, the viscosity at the initial stage of mixing at the time of preparing the composition, the hardness of the test piece after standing at 150 ° C. for 300 hours (type A and type D) and the initial stage The thermal conductivity of was evaluated. The test results are also shown in Table 2. Each test method is as follows.

(viscosity)
(I) The viscosity of the polyol component was measured at 25 ° C. using a BH viscometer.

(Hardness (Type A and Type D))
Hardness (type A and type D) was measured according to JIS K6253.

(Thermal conductivity)
The thermal conductivity is 6 cm × 12 cm × 1 cm polyurethane resin prepared by the above method, left at 25 ° C. for 24 hours, and probed using a thermal conductivity meter (QTM-D3 manufactured by Kyoto Electronics Industry Co., Ltd.) Measured by the method.

(Evaluation results)
As can be seen from Examples 1 to 8, it is understood that the two-component reactive polyurethane resin composition of the present invention has a viscosity at which a polyol can be used and has excellent thermal conductivity and heat resistance. .

  On the other hand, when the phosphate ester is not used as in Comparative Examples 1 and 3, the viscosity of the polyol component becomes very high, and the viscosity of the mixed solution with the isocyanate component becomes very high, thereby producing a polyurethane resin. I couldn't.

  Moreover, when the polybutadiene polyol with a high iodine value is used like the comparative example 2, it turns out that the hardness raise in high temperature conditions is large, and flexibility is inferior.

  If the two-component reactive polyurethane resin composition of the present invention is used, the resulting polyurethane resin has excellent heat dissipation and can maintain flexibility over a long period of time. It is possible to use.

Claims (5)

A two-component reactive polyurethane resin composition comprising (I) a polyol component and (II) an isocyanate component,
(I) the polyol component is
(A) hydrogenated polyisoprene polyol;
(B) castor oil-based polyol;
(C) a phosphate ester represented by the general formula (1);
(D) containing an inorganic filler ,
When the total amount of (I) a polyol component and (II) an isocyanate component is 100 wt%, (D) an inorganic filler 2-liquid reaction type polyurethane resin composition characterized that you containing 50 to 95 wt% .

(R is a hydrocarbon group having 1 to 30 carbon atoms, m is an integer of 0 to 20, n is an integer of 1 to 20, R ′ is OH or a group represented by the general formula (2), and the general formula (1) In the general formula (2), R ″ is CH ₃ or CH ₂ CH ₃ , and “/” represents that the oxyalkylene groups described on the left and right thereof may be block addition or random addition.
  When the total amount of (I) polyol component and (II) isocyanate component is 100% by weight, (C) the phosphoric acid ester represented by the general formula (1) is contained in an amount of 0.01 to 5% by weight. The two-component reactive polyurethane resin composition according to claim 1. The two-component reactive polyurethane resin composition according to claim 1 or 2 , further comprising (E) a plasticizer. The two-component reactive polyurethane resin composition according to any one of claims 1 to 3 , which is used for electric and electronic parts. Electrical and electronic parts produced using the two-liquid reaction type polyurethane resin composition according to any one of claims 1 to 4.