JP2019006957A - Polyurethane resin composition for cutting work - Google Patents

Abstract

To provide a polyurethane resin composition for cutting work that has sufficient strength and heat resistance for cutting work, and excellent antistatic properties.SOLUTION: The present invention provides a polyurethane resin composition for cutting work (X) that contains polyol (A), polyisocyanate (B), and alkali metal salt and/or alkaline earth metal salt (C) as constituent materials, the polyol (A) having polyol (a1) with a hydroxyl value of 400-1,000 (unit: mgKOH/g) and an average functional group number of 3 or more, and polyol (a2) with a hydroxyl value of 28-160, at a weight ratio (a1)/(a2) of 30/70-70/30.SELECTED DRAWING: None

Description

  The present invention relates to a polyurethane resin composition for machining. The present invention relates to an antistatic polyurethane resin composition excellent in cutting workability and imparting antistatic properties to a molded product.

In general, as a method of imparting antistatic properties to a polyurethane resin, a method of adding a surfactant from the viewpoint of ionic conduction and adding carbon black from the viewpoint of electrical conduction is known (for example, Patent Document 1).
However, in order to develop antistatic properties by ion conduction, in order to make it easier to move ions in the resin, it is limited to soft polyurethane, and hard polyurethane resins did not exhibit antistatic properties (for example, Patent Document 2).
On the other hand, since the antistatic agent that exhibits electrical conductivity by carbon black only needs to be in contact with each other in the resin, it exhibits an antistatic function with a wide range of soft to hard resins. There was a problem that the surroundings became dirty due to the removal of cutting powder or carbon black due to processing.
Further, heat resistance is also required because frictional heat is generated when cutting with a high-speed rotating end mill or the like.

Japanese Patent Application Laid-Open No. 07-18150 JP 2002-146178 A

  The subject of this invention is providing the polyurethane resin composition which was excellent in the intensity | strength which can endure the said problem, and can endure cutting, heat resistance, and antistatic property.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
That is, the present invention is a polyurethane resin composition obtained by curing a polyol (A), a polyisocyanate (B), an alkali metal salt and / or an alkaline earth metal salt (C) as constituent raw materials, The polyol (A) is a weight of a polyol (a1) having a hydroxyl value of 400 to 1,000 (unit: mg KOH / g) and an average functional group number of 3 or more and a polyol (a2) having a hydroxyl value of 28 to 160. This is a polyurethane resin composition for cutting (X) containing (a1) / (a2) in a ratio of 30/70 to 70/30.

  The cured polyurethane resin composition for cutting work according to the present invention has excellent heat resistance due to high deflection temperature under load, high shore hardness, excellent strength enough to withstand cutting work, and low surface resistivity. Excellent antistatic properties.

Examples of the polyol (A) of the present invention include the following polyoxyalkylene polyol (A1), polyester polyol (A2), and mixtures thereof.
Polyoxyalkylene polyol (A1)
Polyhydric alcohols such as ethylene glycol, glycerin and propylene glycol; amines such as triethanolamine, ethylenediamine and toluenediamine; starting materials such as polyhydric phenols such as bisphenol A and bisphenol F; alkylene oxide (hereinafter abbreviated as AO) It is a compound to which is added.
As AO to be added, those having 2 to 8 carbon atoms are preferable, and propylene oxide (hereinafter sometimes abbreviated as PO), ethylene oxide (hereinafter sometimes abbreviated as EO), butylene oxide (hereinafter referred to as PO). May be abbreviated as BO.), Etc., and two or more may be used, but preferred are PO, EO, and a combination of PO and EO.

Polyester polyol (A2)
Polyhydric alcohols [ethylene glycol, diethylene glycol, propylene glycol, 1,3- or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol and other dihydric alcohols; glycerin, trimethylolpropane, etc. 3 Polyoxyalkylene polyol and polycarboxylic acid (for example, adipic acid, sebacic acid, etc.) or an ester-forming derivative thereof [acid anhydride (maleic anhydride, phthalic anhydride, etc.), Lower alkyl (alkyl group having 1 to 4 carbon atoms) ester (such as dimethyl terephthalate)]; polylactone polyol [obtained by ring-opening polymerization of lactone (such as ε-caprolactone) using the polyhydric alcohol as an initiator Polycarbonate poly Lumpur, for example a reaction product of the polyhydric alcohol and alkylene carbonate; and the like.

The polyol (A) of the present invention includes a polyol (a1) having a hydroxyl value of 400 to 1,000 (unit: mg KOH / g) and an average functional group number of 3 or more, and a polyol (a2) having a hydroxyl value of 28 to 160. And (a1) / (a2) in a weight ratio of 30/70 to 70/30.
If it is less than 30/70, the heat resistance is deteriorated, and if it exceeds 70/30, the antistatic property is deteriorated. Preferably it is 35 / 65-65 / 35, More preferably, it is 40 / 60-60 / 40.

The hydroxyl value (unit: mgKOH / g) of the polyol (a1) is 400 to 1000, preferably 400 to 1000, more preferably 420 to 800, and particularly preferably 450 to 700. When the hydroxyl value is less than 400, the molded product of the urethane reaction cured product when combined with the polyol (a2) described later is insufficient in heat resistance and is not suitable for cutting. On the other hand, when the hydroxyl value exceeds 1,000, the antistatic property of the molded product cannot be obtained even when combined with the polyol (a2).

The average number of functional groups of the polyol (a1) is 3 or more. If it is less than 3, since it will not bridge | crosslink, heat resistance will worsen.

The hydroxyl value of the polyol (a2) is 28 to 160, preferably 36 to 145, more preferably 44 to 135, and particularly preferably 56 to 112. When the hydroxyl value is less than 28, the heat resistance is remarkably lowered, and the heat resistance of the molded product cannot be obtained even when combined with the polyol (a1). When the hydroxyl value exceeds 160, when combined with the polyol (a1), the antistatic performance of the molded product cannot be obtained.

<Polyisocyanate (B)>
The polyisocyanate (B) in the present invention is not particularly limited as long as it is a compound having two or more isocyanate groups in the molecule.
Examples of (B) include aromatic polyisocyanate (B1), aliphatic polyisocyanate (B2), alicyclic polyisocyanate (B3), araliphatic polyisocyanate (B4), and modified products thereof (B5) (for example, Urethane group, carbodiimide group, allophanate group, urea group, burette group, isocyanurate group, or oxazolidone group-containing modified product). (B) may be used alone or in combination of two or more.

The aromatic polyisocyanate (B1) includes 6 to 16 aromatic diisocyanates, 6 to 20 aromatic triisocyanates, and these isocyanates (not including carbon in the NCO group; the following isocyanates are also included). Crude product. Specific examples include 1,3- and / or 1,4-phenylene diisocyanate, 2,4- and / or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4′- and / or 4, 4'-diphenylmethane diisocyanate (MDI), polymethylene polyphenylene polyisocyanate (crude MDI or polymeric MDI), and the like.

Examples of the aliphatic polyisocyanate (B2) include aliphatic diisocyanates having 6 to 10 carbon atoms. Specific examples include 1,6-hexamethylene diisocyanate and lysine diisocyanate.

Examples of the alicyclic polyisocyanate (B3) include alicyclic diisocyanates having 6 to 16 carbon atoms. Specific examples include isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate, norbornane diisocyanate and the like.

Examples of the araliphatic polyisocyanate (B4) include araliphatic diisocyanates having 8 to 12 carbon atoms. Specific examples include xylylene diisocyanate, α, α, α ′, α′-tetramethylxylylene diisocyanate, and the like.

Specific examples of the modified polyisocyanate (B5) include urethane-modified MDI and carbodiimide-modified MDI.

Among the above (B), it is preferable to use aromatic polyisocyanate (B1) and a modified product thereof from the viewpoint of solvent resistance.
The isocyanate group content in the polyisocyanate (B) is preferably 35 to 60% by weight.

<Alkali metal salt / Alkaline earth metal salt (C)>
As the alkali metal salt and alkaline earth metal salt (C) in the present invention, commercially available alkali metal salts and alkaline earth metal salts can be used, but lithium salts are preferred from the viewpoint of antistatic performance.

The alkali metal salt / alkaline earth metal salt (C) is preferably (perfluoroalkylsulfonyl) imide lithium salt or (perfluoroalkylsulfonyl) methane lithium salt from the viewpoint of ionic conductivity.

The total amount of alkali metal salt and alkaline earth metal salt (C) used is 0.1 weight based on the total weight of polyol (A) and polyisocyanate (B) from the viewpoint of antistatic performance and cost of the composition. % To 2.0% by weight, preferably 0.1% to 1.5% by weight, and more preferably 0.1% to 1.0% by weight.

<Cutting polyurethane resin composition (X)>
The polyurethane resin composition for cutting work (X) of the present invention comprises a polyol (a1) having a hydroxyl value of 400 to 1,000 and an average functional group number of 3 or more, and a polyol (a2) having a hydroxyl value of 28 to 160. ) -Containing polyol (A), polyisocyanate (B), and an alkali metal salt / alkaline earth metal salt (C) as an antistatic agent, obtained by curing.
The polyurethane resin composition (X) is obtained, for example, by mixing and reacting the above constituent raw materials and, if necessary, a urethanization catalyst, a dehydrating agent, and other additives in a container.

When the ratio of the polyol (A) and the polyisocyanate (B) is represented by an isocyanate index [(equivalent ratio of NCO group / OH group) × 100], the index can be variously changed, preferably 80 to 140, More preferably, it is 85-120, Most preferably, it is 90-115.

Moreover, as a reaction method of a polyol (A) and a polyisocyanate (B), even if it is a one shot method, after reacting a part of (A) and (B) beforehand and forming an NCO terminal prepolymer In the prepolymer method in which the remaining (A) is reacted, or a part of (A) and (B) are reacted in advance to form an OH-terminated prepolymer and then reacted with the remaining (B). There may be.

As the urethanization catalyst used as a part of the constituent raw materials of the polyurethane resin composition (X) of the present invention, all usual urethanization catalysts that accelerate the urethanization reaction can be used.
For example, triethylenediamine, bis (N, N-dimethylamino-2-ethyl) ether, N, N, N ′, N′-tetramethylhexamethylenediamine, N, N-dimethylaminopropylamine PO adduct, etc. Examples thereof include tertiary amines and their carboxylates, carboxylic acid metal salts such as potassium acetate, potassium octylate and stannous octoate, and organometallic compounds such as dibutyltin dilaurate.

<Molded product (D)>
The molded product of the present invention is formed by molding, cutting, cutting, cutting, punching, hot pressing, etc., the polyurethane resin composition (X) that has undergone curing reaction.

The deflection temperature under load of the molded product of the present invention is an index representing heat resistance, preferably 60 ° C. or higher, more preferably 65 ° C. or higher, and particularly preferably 70 ° C. or higher.
If the deflection temperature under load is less than 60 ° C., the molded product is likely to be distorted by heat generated during cutting.
The molded product is further cut by an NC machine or the like to obtain a model or mold. The model and mold are not easily cracked or distorted.

The surface specific resistance value of the molded product of the present invention is preferably 1.0 × 10 ¹² Ω / □ or less, 1.0 × 10 6 from the viewpoint of reliability of components and antistatic properties when used for electronic components and the like. ¹¹ Ω / □ or less, particularly preferably 1.0 × 10 ¹⁰ Ω / □ or less.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

Example 1
Sorbitol PO adduct (a1-1) 28.1 parts, Glycerin PO adduct (a1-1) 28.1 parts, Polymeric MDI 38.2 parts, (trifluoromethanesulfonyl) imide lithium salt 50% tetraglyme solution 0.9 parts, 0.01 parts of bismuth tris (2 ethylhexanoate) and 4.7 parts of a dehydrating agent were stirred for 15 minutes at 300 rpm under vacuum using a commercially available vacuum stirring deaerator. And evenly mixed. The mixture is poured into a mold having a size of 300 mm in length, 300 mm in width, and 100 mm in height, and cured at 100 ° C. for 10 hours in a curing furnace, whereby the polyurethane resin composition for cutting work of the present invention ( X-1) was obtained.

Examples 2-9, Comparative Examples 1-6
The components in parts by weight shown in Table 1 were stirred and uniformly mixed using a vacuum stirring and defoaming machine in the same manner as in Example 1, and then heat-cured in a curing furnace, whereby antistatic properties for cutting in Examples were Polyurethane resin compositions (X-2) to (X-9) and comparative examples (X′-1) to (X′-6) were obtained.

In addition, the raw material of the polyurethane resin used in Examples 1-9 and Comparative Examples 1-6 described in Table 1 is as follows.
Polyol (a1-1): PO adduct of sorbitol having a hydroxyl value of 490, an average functional group number of 6.0, and a number average molecular weight of 750 [trade name “SANNICS SP-750” manufactured by Sanyo Chemical Industries, Ltd.]
Polyol (a1-2): PO adduct of glycerin having a hydroxyl value of 673, an average functional group number of 3.0, and a number average molecular weight of 250 [trade name “Sanix GP-250” manufactured by Sanyo Chemical Industries, Ltd.]
Polyol (a1-3): PO adduct of glycerin having a hydroxyl value of 400, an average functional group number of 3.0, and a number average molecular weight of 420 [trade name “Sanix GP-400” manufactured by Sanyo Chemical Industries, Ltd.]
Diethylene glycol (a1′-1): hydroxyl value 1,058, average functional group number 2.0, number average molecular weight 106
Polyol (a2-1): PO adduct of glycerin having a hydroxyl value of about 56, an average number of functional groups of 3.0, and a number average molecular weight of 3,000 [trade name “Sanix GP-3000” manufactured by Sanyo Chemical Industries, Ltd. ]
Polyol (a2-2): PO adduct of glycerin having a hydroxyl value of 160, an average functional group number of 3.0, and a number average molecular weight of 1,000 [trade name “Sanix GP-1000” manufactured by Sanyo Chemical Industries, Ltd.]
Polyol (a2-3): PO adduct of propylene glycol having a hydroxyl value of 112, an average number of functional groups of 2.0, and a number average molecular weight of 1,000 [trade name “SANNICS PP-1000” manufactured by Sanyo Chemical Industries, Ltd. ]
Polyol (a2′-1): PO adduct of propylene glycol having a hydroxyl value of 27, an average functional group number of 2.0, and a number average molecular weight of 5000 [trade name “New Pole PP-4000” manufactured by Sanyo Chemical Industries, Ltd. ]

Isocyanate (B-1): Polymeric MDI [trade name “Lupranate M20S”, manufactured by BASF INOAC Polyurethane Co., Ltd., isocyanate group content 31.5% by weight]
Isocyanate (B-2): Isophorone diisocyanate [trade name “VESTANAT IPDI”, manufactured by EVONIC, isocyanate group content 37.6% by weight]

Alkali metal salt / alkaline earth metal salt (C-1): 50% tetraglyme solution of lithium salt of (trifluoromethanesulfonyl) imide [trade name “Sanconol TGR”, manufactured by Sanko Chemical Co., Ltd.]
Alkali metal salt / alkaline earth metal salt (C-2): 20% PPG solution of lithium salt of (trifluoromethanesulfonyl) imide [trade name “Sanconol PEO-20R”, manufactured by Sanko Chemical Co., Ltd.]
Urethane catalyst: “Neostan U-600” manufactured by Nitto Kasei Co., Ltd.
Dehydrating agent: "Molecular sieve 3A-B powder" manufactured by Union Showa Co., Ltd.

About these polyurethane resin compositions (X-1) to (X-9) and (X′-1) to (X′-6) of Comparative Examples 1 to 6, The deflection temperature under load, (2) surface resistivity, (3) Shore D hardness, and (4) density were measured by the following methods.
The results are shown in Table 2.

(1) Deflection temperature under load (HDT)
A cured resin composition is cut into a length of 127 mm, a width of 12.7 mm, and a thickness of 12.7 mm to obtain a test piece. A load of 1.8 MPa is applied at a distance between fulcrums of 100 mm, and measured according to JIS K6911. did.
Measurement is a heat distortion tester [Model No. 148-HDPC-3] manufactured by Yasuda Seiki Seisakusho Co., Ltd. was used.
From the viewpoint of heat resistance during cutting, the deflection temperature under load under this measurement condition is generally required to be 60 ° C. or higher.

(2) Surface resistivity (unit: Ω / □):
After the surface of the resin composition, which is a cured product, is cut by 1 mm to remove the skin layer on the surface portion and the cutting powder remaining on the cutting surface is well removed, a surface resistance meter ST-4 (manufactured by Simco Japan) is used. The surface resistivity of the cut surface was measured.
Under these measurement conditions, generally 10 ¹² Ω / □ or less is required.

(3) Shore D hardness:
A test piece obtained by cutting a resin composition as a cured product into a rectangular parallelepiped shape of 5 cm × 5 cm × thickness 10 mm is measured five times with a type D durometer according to JIS K6253, and an average value is obtained. did.
In order to have good machinability, 50-80 is generally required under this measurement condition.

(4) Density (g / cm3)
A 200 mm × 100 mm × 30 mm test piece was cut out from the center of the resin composition that is a cured product, and the weight of the test piece was calculated from the product of the lengths of the three sides in a room temperature-controlled at 25 ° C. To obtain the density.

The polyurethane compositions for cutting (X) of Examples 1 to 9 of the present invention have a heat resistance of 60 ° C. or higher and a surface resistivity value of 10 ¹² Ω / □ or less, so that the antistatic performance is good. I understand that.
On the other hand, the composition of Comparative Example 1 that does not contain polyol (a2) and Comparative Example 5 in which (a1) / (a2) exceeds 75/25 has poor ionic conductivity because of the small soft segment portion, and has a surface resistivity value. Exceeds 10 ¹² Ω / □.
Moreover, since the composition of the comparative example 2 which does not contain a polyol (a1) and the composition of the comparative example 6 in which (a1) / (a2) exceeds 25/75 has few hard segment parts, its deflection temperature is less than 60 degreeC, and heat resistance is It becomes defective, and since the Shore D hardness is less than 50, the machinability is deteriorated.
The composition of Comparative Example 3 using (a2′-1) instead of (a2) and the composition of Comparative Example 4 using (a1′-1) instead of (a1) is biased in the hard segment or soft segment. As a result, the heat balance or the surface resistivity cannot be achieved.

Since the molded product of the polyurethane composition for cutting (X) of the present invention has excellent heat resistance, it can be suitably used as a material for cutting.
Furthermore, since it has excellent antistatic performance, it is suitable for applications such as jigs for electronic parts that require high-temperature processing, transport trays, and image forming apparatuses such as laser printers.

Claims (6)

  A polyurethane resin composition obtained by curing a polyol (A), a polyisocyanate (B), an alkali metal salt and / or an alkaline earth metal salt (C) as a constituent material, wherein the polyol (A) is: A polyol (a1) having a hydroxyl value of 400 to 1,000 (unit: mg KOH / g) and an average number of functional groups of 3 or more and a polyol (a2) having a hydroxyl value of 28 to 160 by weight ratio (a1) / ( The polyurethane resin composition (X) for cutting which a2) contains by 30 / 70-70 / 30. The polyurethane resin composition for cutting according to claim 1, wherein the surface resistance value is 1.0 × 10 ¹² Ω / □ or less. The polyurethane resin composition for cutting according to claim 1 or 2, wherein the deflection temperature under load is 60 ° C or higher. The polyurethane resin composition for cutting according to any one of 1 to 3, wherein the alkali metal salt and / or alkaline earth metal salt (C) is (perfluoroalkylsulfonyl) imide lithium salt / or (perfluoroalkylsulfonyl) methane lithium salt. object.   The polyurethane resin composition for cutting according to any one of claims 1 to 4, wherein the content of (C) is 0.1 to 2.0% by weight based on the total weight of (A) and (B). . A polyurethane resin molded product obtained by molding the polyurethane resin composition for cutting (X) according to any one of claims 1 to 5.