JP7289568B1 - POLYURETHANE RESIN COMPOSITIONS, SEALING MATERIALS AND ELECTRICAL AND ELECTRONIC COMPONENTS - Google Patents

Abstract

An object of the present invention is to provide a polyurethane resin composition from which a foamed polyurethane resin having a sufficient expansion ratio can be produced. A polyurethane resin composition containing an isocyanate group-containing compound, a hydroxyl group-containing compound, and water, wherein the water content in the polyurethane resin composition is 0.35% by mass or more. A polyurethane resin composition characterized by: [Selection figure] None

Description

TECHNICAL FIELD The present invention relates to a polyurethane resin composition, a sealing material and an electric/electronic component.

2. Description of the Related Art In recent years, the density and integration of electrical and electronic components have been increasing, and each component is required to be improved in reliability.

In order to protect these electrical and electronic components, sealing with a sealing material is performed, and foamed polyurethane resin is used as such a sealing material (see, for example, Patent Document 1).

A foamed polyurethane resin used for such a sealing material is required to have a sufficient foaming ratio in order to achieve weight reduction and exhibit impact resistance and the like. As a result of intensive studies, the inventors have found that when the content of water in the polyurethane resin composition is low, the foaming ratio of the foamed polyurethane resin is not sufficient. The polyurethane resin composition for producing the foamed polyurethane resin described in Patent Document 1 contains 0.35 parts by mass or less of water per 100 parts by mass of the polyurethane resin composition, and the foaming ratio is insufficient. There is

Therefore, there is a demand for development of a polyurethane resin composition capable of producing a foamed polyurethane resin having a sufficient expansion ratio.

Japanese Unexamined Patent Application Publication No. 2020-35640

An object of the present invention is to provide a polyurethane resin composition from which a foamed polyurethane resin having a sufficient expansion ratio can be produced.

As a result of extensive research, the present inventors have found that, in a polyurethane resin composition containing an isocyanate group-containing compound, a hydroxyl group-containing compound, and water, the content of water in the polyurethane resin composition is 0.35% by mass. The inventors have found that the above-described object can be achieved with the configuration described above, and have completed the present invention.
That is, the present invention relates to the following polyurethane resin composition, encapsulant and electric/electronic component. 1. A polyurethane resin composition containing an isocyanate group-containing compound, a hydroxyl group-containing compound, and water,
The water content in the polyurethane resin composition is 0.35% by mass or more.
A polyurethane resin composition characterized by:
2. Item 2. The polyurethane resin composition according to Item 1, wherein the water content in the polyurethane resin composition is 0.60% by mass or more.
3. Item 3. The polyurethane resin composition according to Item 1 or 2, further comprising a foam stabilizer, wherein the foam stabilizer has an HLB of 3 to 11.
4. Furthermore, it contains a flame retardant, and the flame retardant is at least one selected from the group consisting of phosphate ester compounds, melamine compounds, phosphorus/nitrogen compounds, halogen compounds, metal hydrates, and expandable graphite. Item 4. The polyurethane resin composition according to any one of Items 1 to 3, wherein
5. 5. Any one of Items 1 to 4, wherein the hydroxyl group-containing compound contains a polyol having a polybutadiene skeleton, and the content of the polyol having a polybutadiene skeleton is 10% by mass or more with respect to 100% by mass of the polyurethane resin composition. The polyurethane resin composition described.
6. A sealing material comprising the polyurethane resin composition according to any one of Items 1 to 5.
7. Item 7. An electric/electronic component resin-sealed using the sealing material according to item 6.

The polyurethane resin composition of the present invention can produce a foamed polyurethane resin having a sufficient expansion ratio.

The polyurethane resin composition, encapsulant, and electrical/electronic component of the present invention are described in detail below.

The polyurethane resin composition of the present invention is a polyurethane resin composition containing an isocyanate group-containing compound, a hydroxyl group-containing compound, and water, wherein the water content in the polyurethane resin composition is 0.35 mass. % or more. By containing 0.35% by mass or more of water, the polyurethane resin composition of the present invention can be sufficiently foamed, and a foamed polyurethane resin having a sufficient expansion ratio can be produced.

The polyurethane resin composition of the present invention contains water. In the polyurethane resin composition of the present invention, water is a component that acts as a foaming agent.

The polyurethane resin composition of the present invention has a water content of 0.35% by mass or more. If the water content is less than 0.35% by mass, it is not possible to produce a foamed polyurethane resin with a sufficient expansion ratio. The content of water is preferably 0.50% by mass or more, more preferably 0.60% by mass or more. Moreover, the content of water is preferably 1.00% by mass or less, more preferably 0.80% by mass or less. When the upper limit of the water content is within the above range, the polyurethane resin composition can control the curability while maintaining a sufficient expansion ratio, thereby suppressing shrinkage.

(Isocyanate group-containing compound)
The isocyanate group-containing compound used in the polyurethane resin composition of the present invention is not particularly limited, and various compounds conventionally used as isocyanate group-containing compounds in polyurethane resin compositions can be used. Examples of the isocyanate group-containing compounds include aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, aromatic polyisocyanate compounds and araliphatic polyisocyanate compounds.

Aliphatic polyisocyanate compounds include tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2- Examples thereof include methylpentane-1,5-diisocyanate and 3-methylpentane-1,5-diisocyanate.

Examples of alicyclic polyisocyanate compounds include isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, and the like. are mentioned.

Examples of aromatic polyisocyanate compounds include tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 4,4′-dibenzyl diisocyanate, 1, 5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate and the like.

Examples of araliphatic polyisocyanate compounds include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, α,α,α,α-tetramethylxylylene diisocyanate and the like.

The isocyanate group-containing compound may contain an isocyanurate modified product and/or an allophanate modified product of the above polyisocyanate compound. By including an isocyanurate-modified polyisocyanate compound and/or an allophanate-modified polyisocyanate compound in the isocyanate group-containing compound, the polyurethane resin composition exhibits superior heat resistance and flame retardancy. can be done.

The above isocyanate group-containing compounds may be used alone, or two or more of them may be mixed and used.

The amount of the isocyanate group-containing compound used in the polyurethane resin composition of the present invention is preferably 1 to 30% by mass, more preferably 4 to 20% by mass, based on 100% by mass of the polyurethane resin composition. When the upper limit of the content of the isocyanate group-containing compound is within the above range, the curability of the polyurethane resin composition is further improved. When the lower limit of the content of the isocyanate group-containing compound is within the above range, the hydrolysis resistance and curability of the cured polyurethane resin composition are further improved.

(Hydroxyl group-containing compound)
The hydroxyl group-containing compound used in the polyurethane resin composition of the present invention is not particularly limited, and various compounds conventionally used as polyol components in polyurethane resin compositions can be used.

Examples of the hydroxyl group-containing compound include polybutadiene polyol, ethylene glycol, 1,3-propanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, and 1,3-butane. Diol, 1,4-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,2-hexanediol, 2,5-hexanediol, octanediol, nonanediol, decane Diol, diethylene glycol, triethylene glycol, dipropylene glycol, cyclohexanediol, trimethylolpropane, glycerin, 2-methylpropane-1,2,3-triol, 1,2,6-hexanetriol, pentaerythritol, polylactone diol , polylactone triol, ester glycol, castor oil-based polyol, polyolefin polyol, polyester polyol, polyether polyol, polycarbonate polyol, acrylic polyol, silicone polyol, fluorine polyol, polytetramethylene glycol, polytetramethylene ether glycol, polypropylene glycol, polyethylene Glycol, polycaprolactone polyol, hydride of hydroxyl group-containing liquid polyisoprene, hydride of hydroxyl group-containing liquid polybutadiene, and the like.

The hydroxyl group-containing compound preferably contains a polyol having a polybutadiene skeleton. When the hydroxyl group-containing compound contains a polyol having a polybutadiene skeleton, the hydrolysis resistance of the polyurethane resin composition of the present invention is further improved.

The content of the polyol having a polybutadiene skeleton is preferably 10% by mass or more, more preferably 15% by mass or more, based on 100% by mass of the polyurethane resin composition. The content of the polyol having a polybutadiene skeleton is preferably 35% by mass or less, more preferably 30% by mass or less, based on 100% by mass of the polyurethane resin composition. By setting the lower limit of the content of the polyol having a polybutadiene skeleton within the above range, the hydrolysis resistance of the polyurethane resin composition of the present invention is further improved. When the upper limit of the content of the polyol having a polybutadiene skeleton is within the above range, the polyurethane resin composition of the present invention can maintain hydrolysis resistance and flame retardancy, and further improve curability.

Among polyols having a polybutadiene skeleton, polybutadiene polyols are preferably used. The polybutadiene polyol, for example, has a repeating unit composed of polybutadiene having 60 to 90 mol% of 1,4 bonds and 10 to 40 mol% of 1,2 bonds, the number of repetitions is 10 to 100, and both Examples include polyols having terminal hydroxyl groups.

The amount of the hydroxyl group-containing compound used in the polyurethane resin composition of the present invention is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on 100% by mass of the polyurethane resin composition. When the upper limit of the content of the hydroxyl group-containing compound is within the above range, the curability of the polyurethane resin composition of the present invention is further improved. When the lower limit of the content of the hydroxyl group-containing compound is within the above range, the hydrolysis resistance of the polyurethane resin composition of the present invention is further improved.

In the polyurethane resin composition of the present invention, the NCO/OH ratio between the isocyanate group-containing compound and the hydroxyl group-containing compound is preferably 0.6 to 2.0, more preferably 0.7 to 1.5. is more preferred. When the lower limit of the NCO/OH ratio is within the above range, the heat resistance of the polyurethane resin composition is further improved. When the upper limit of the NCO/OH ratio is within the above range, the curability of the polyurethane resin composition is further improved.

(foam stabilizer)
The polyurethane resin composition of the present invention preferably contains a foam stabilizer. The foam stabilizer is not particularly limited, and various foam stabilizers conventionally used in polyurethane resin compositions can be used.

Examples of the foam stabilizer include silicone foam stabilizers and non-silicone foam stabilizers. Among these, silicone-based foam stabilizers are preferred because of their higher surface activity.

Examples of silicone-based foam stabilizers include dimethylsiloxane-based compounds, polyetherdimethylsiloxane-based compounds, and phenylmethylsiloxane-based compounds, and block polymers of these may be used. Examples of such block polymers include dimethylpolysiloxane compounds such as dimethylsilicone oil, and polyether-modified silicones, which are polyether block polymers.

The above foam stabilizers may be used singly or in combination of two or more.

The HLB of the foam stabilizer is preferably 3-11, more preferably 3-10, and even more preferably 3-8. When the HLB of the foam stabilizer is within the above range, poor curing of the polyurethane resin composition can be further suppressed. In general, when a powdery flame retardant is added to impart flame retardancy to a polyurethane resin composition, the hardness of the polyurethane resin composition increases, so the blending amount cannot be increased. Therefore, in order to impart flame retardancy to the polyurethane resin composition, it is necessary to blend a large amount of a liquid flame retardant as the flame retardant. However, when a large amount of the liquid flame retardant is mixed, the resin skeleton becomes weak and poor curing (shrinkage) occurs. In the polyurethane resin composition of the present invention, by using the HLB foam stabilizer in the above specific range, poor curing of the polyurethane resin composition can be further suppressed.

Commercially available products can be used as the foam stabilizer. Examples of such commercial products include SH-192 (HLB=7), PRX-609 (HLB=5) and SZ-1333 (HLB=3) manufactured by Dow Toray Industries, Inc.

The content of the foam stabilizer is preferably 0.1 to 5% by mass, more preferably 0.1 to 3% by mass, still more preferably 0.2 to 1% by mass, based on 100% by mass of the polyurethane resin composition. When the upper limit of the content of the foam stabilizer is within the above range, poor curing of the polyurethane resin composition can be further suppressed.

(Flame retardants)
The polyurethane resin composition of the present invention may contain a flame retardant. The flame retardant is not particularly limited, and various flame retardants conventionally used in polyurethane resin compositions can be used.

Examples of flame retardants include phosphoric acid ester compounds, melamine compounds, phosphorus/nitrogen compounds, halogen compounds, metal hydrates, and expandable graphite.

The content of the flame retardant is preferably 30 to 80% by mass, more preferably 50 to 70% by mass, based on 100% by mass of the polyurethane resin composition. When the upper limit of the content of the flame retardant is within the above range, the hydrolysis resistance of the polyurethane resin composition is further improved. When the lower limit of the content of the flame retardant is within the above range, the flame retardancy of the polyurethane resin composition is further improved.

(Other additives)
Various additives such as catalysts, antioxidants, hygroscopic agents, antifungal agents, silane coupling agents and the like can be added to the polyurethane resin composition of the present invention, if necessary.

Although the catalyst is not particularly limited, conventionally known catalysts used in urethane resin compositions can be used. Examples of such catalysts include tin catalysts such as dioctyltin dilaurate, dibutyltin dilaurate and dioctyltin diacetate; lead catalysts such as lead octylate, lead octenoate and lead naphthenate; bismuth such as bismuth octylate and bismuth neodecanoate. Catalysts, amine-based catalysts such as diethylenetriamine and triethylenediamine, and the like. Moreover, an organic metal compound, a metal complex compound, or the like may be used as the catalyst.

The amount of these additives to be used may be appropriately determined according to the purpose of use from the usual addition amount and the identification range so as not to impair the desired properties of the polyurethane resin composition.

(Method for producing polyurethane resin composition)
The method for producing the polyurethane resin composition of the present invention is not particularly limited, and it can be produced by a conventionally known method used as a method for producing a polyurethane resin composition.

As such a production method, for example, a component containing an isocyanate group-containing compound is prepared as agent A, a component containing a hydroxyl group-containing compound is prepared as agent B, and agent A and agent B are mixed to react. As a polyurethane resin, there is a method for producing a polyurethane resin composition containing the polyurethane resin.

As long as the A agent contains an isocyanate group-containing compound and the B agent contains a hydroxyl group-containing compound, the other components may be contained in either the A agent or the B agent. Moreover, it is good also as a prepolymer by adding a hydroxyl-containing compound to A agent.

The polyurethane resin composition may be in a liquid state before curing, or may be in a cured state. As a method for curing the polyurethane resin composition, by mixing the components A and B, the isocyanate group-containing compound and the hydroxyl group-containing compound are reacted to form a polyurethane resin, thereby curing the polyurethane resin composition over time. A method of curing may be used, but curing may be performed by heating. In this case, the heating temperature is preferably about 20 to 120° C., and the heating time is preferably about 0.1 to 24 hours.

The present invention also provides a sealing material comprising the above polyurethane resin composition. The sealing material made of the polyurethane resin composition can be suitably used for electric/electronic parts, electric/electronic parts that generate heat, and the like. Such electrical and electronic components include transformers such as transformer coils, choke coils and reactor coils, equipment control boards, and various sensors. Such an electric/electronic component is also one aspect of the present invention. The electrical/electronic component of the present invention can be used in electric washing machines, toilet seats, water heaters, water purifiers, baths, dishwashers, power tools, automobiles, motorcycles, battery packs and the like.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to the examples.

Raw materials used in Examples and Comparative Examples are shown in Table 1 below.

(Preparation of polyurethane resin composition)
The raw materials of the composition of the B agent shown in Table 2 were put into a reaction vessel and stirred for 1 hour at normal temperature and normal pressure to prepare a polyol component (B agent).

As a raw material for preparing a polyisocyanate component, an isocyanate group-containing compound (MR-200) was prepared as isocyanate a-1. Flame retardant c-1 (TCP) is charged into a reaction vessel equipped with a heating, cooling, and decompression device, dehydrated at 60 ° C. under a pressure of 10 mmHg or less for 1 hour, then isocyanate a-1 is charged, and 60 C. and a pressure of 10 mmHg or less for 1 hour to effect dehydration and reaction to prepare a polyisocyanate component (agent A) using isocyanate a-1.

Also, as shown in Table 1, R-45HT and PL-2100 were prepared as polyols for preparing prepolymers isocyanate a-2 and isocyanate a-3. R-45HT or PL-2100 and flame retardant c-1 (TCP) are put into a reaction vessel equipped with a heating, cooling, and decompression device, and dehydrated at 100°C under a pressure of 10 mmHg or less for 1 hour. , Isocyanate a-1 is added, dehydration and reaction are performed for 1 hour at 60 ° C. and a pressure of 10 mmHg or less, and a polyisocyanate component (agent A) using isocyanate a-2 or isocyanate a-3 is added. prepared.

A polyurethane resin composition was obtained by adding agent A to agent B according to the formulation shown in Table 2, stirring, defoaming, and mixing. Mixing of B agent and A agent is carried out by adjusting the polyol component (B agent) to 23° C., then adding the polyisocyanate component (A agent) adjusted to 23° C., and mixing with an electric hand mixer (Miracles No. 1123, Pearl Metal Co., Ltd.) was used to stir at 1000 rpm for 1 minute.

(Preparation of test piece)
The prepared polyurethane resin composition was injected into a molding mold A of 130×130×5 mm, a molding mold B of 130×130×10 mm and a molding mold C of 30 mm inner diameter and 20 mm height. Each was allowed to stand at room temperature for 16 hours to cure, and test pieces A, B and C were prepared. Using the prepared test pieces A, B and C, the cured product appearance, flame retardancy and hydrolysis resistance were tested by the methods described below.

Using the polyurethane resin compositions of Examples and Comparative Examples prepared as described above and test pieces, the following tests were carried out.

Using a casting mold (15 × 15 × 43 mm), 3.0 g of resin after stirring and mixing was poured, and after 16 hours at 23 ° C., the upper surface of the foam protruding from the mold was cut using a cutter knife. It was cut flush to prepare a test piece for calculating the expansion ratio. After measuring the length, width and height of the test piece using an electronic caliper and calculating the volume (V), the weight (W) of the test piece was measured using an electronic balance. The calculated and measured values were substituted into the following formula to calculate the specific volume as the expansion ratio of the cured product.
(Expansion ratio) (cm ³ /g) = [V: volume of test piece (cm ³ )] / [W: weight of test piece (g)]

Appearance of cured product (curability): After curing to the touch, measure 20 g of the resin composition after mixing and stirring in a molding die C with an inner diameter of 30 mm and a height of 20 mm, leave it at 23 ° C., and apply a matchstick on the surface of the cured product. After confirming that the resin no longer adheres to the matchstick (after curing to the touch) when the end of the test piece C is pressed and pulled up, the appearance of the test piece C, which is a polyurethane resin composition, is visually observed to determine the curability. evaluated. If there was no shrinkage, it was rated as "good"; if it was, it was rated as "shrinkage".

Appearance of Cured Product (Curability): After mixing and stirring at 23° C./16 h, the appearance of test piece C, which is a polyurethane resin composition left at 23° C. for 16 hours, was visually observed to evaluate curability. If there was no shrinkage, it was rated as "good"; if it was, it was rated as "shrinkage".

A flame retardancy test was conducted using test pieces A and B, which are polyurethane resin compositions after flame retardancy curing. Testing was performed by Underwriters Laboratories, Inc., USA. It was carried out based on the combustion test standard (UL94) established by. Flame retardancy was evaluated according to the following evaluation criteria.
○: Satisfies V-0 ×: Does not satisfy V-0 (V-1, V-2 or HB)

A pressure cooker test was performed under the conditions of 121° C., 100% RH and 2 atm using test piece C, which is a hydrolysis-resistant cured polyurethane resin composition, and the time until test piece C dissolved was measured. Hydrolysis resistance was evaluated according to the following evaluation criteria.
○: Time until dissolution is 80 hours or more ×: Time until dissolution is less than 80 hours

Table 2 shows the results.

The polyurethane resin composition of the present invention can exhibit a sufficient expansion ratio. Therefore, it can be used in fields such as electric appliances.

Claims (6)

A polyurethane resin composition containing an isocyanate group-containing compound, a hydroxyl group-containing compound, and water,
The water content in the polyurethane resin composition is 0.35% by mass or more and 1.00% by mass or less ,
The hydroxyl group-containing compound contains a polyol having a polybutadiene skeleton, and the content of the polyol having a polybutadiene skeleton is 10% by mass or more based on 100% by mass of the polyurethane resin composition,
Furthermore, it contains a silicone foam stabilizer, and the HLB of the silicone foam stabilizer is 5 or less.
A polyurethane resin composition characterized by: 2. The polyurethane resin composition according to claim 1, wherein the content of said water in said polyurethane resin composition is 0.60% by mass or more. 3. The polyurethane resin composition according to claim 1, wherein the silicone foam stabilizer has an HLB of 3 to 5. Furthermore, it contains a flame retardant, and the flame retardant is at least one selected from the group consisting of phosphate ester compounds, melamine compounds, phosphorus/nitrogen compounds, halogen compounds, metal hydrates, and expandable graphite. The polyurethane resin composition according to any one of claims 1 to 3, wherein A sealing material comprising the polyurethane resin composition according to any one of claims 1 to 4 . An electric/electronic component resin-sealed using the sealing material according to claim 5 .