JP3297071B2 - Water / oil repellent composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water- and oil-repellent agent which is particularly effective in imparting high durability to water and oil repellency.

[0002]

2. Description of the Related Art In recent years, water- and oil-repellent finishing of clothing has been actively performed, and various compositions have been provided according to purposes. Sports clothing is required to have high water- and oil-repellent washing and dry cleaning durability, and in order to obtain this durability,
Polyfluoroalkyl group-containing acrylate and vinyl chloride copolymer (JP-B-50-3438 discloses), as further crosslinking component in these monomers N- methylolacrylamide, a copolymer obtained by copolymerizing Gurishijiruakuri rate or the like is proposed ing.

Further, a copolymer containing a functional component which is stable to water at room temperature and releases a -NCO group at a high temperature as an additive (Japanese Patent Application Laid-Open No. 54-131579), a conventional water and oil repellent Water- and oil-repellent (JP-A-54-133486) in which a blocked polyisocyanate compound is mixed with an acrylate copolymer containing a polyfluoroalkyl group and a blocked isocyanate group (JP-A-3-8
And 873 JP) have been proposed, but have such been obtained durability satisfactory yet.

[0004]

An object of the present invention is to provide a is a newly provide child a water and oil repellent compositions that provide high durability has not been known.

[0005]

Means for Solving the Problems The present invention is the following invention which has been made to solve the above-mentioned problems.

(Meth) having a polyfluoroalkyl group
Poly (main with A acrylate (A) and urethane bond
Data) A acrylate (B) as essential components and at least the two monomers copolymerized with the copolymer obtained (C),
And a water / oil repellent composition containing a non-copolymerizable blocked polyisocyanate compound (D).

[0007] (A) in the present invention, a "having a polyfluoroalkyl group (meth) acrylate", hereinafter also referred to as a polyfluoroalkyl group-containing (meth) acrylate. In this specification , (meth) acrylate means both acrylate and methacrylate. (Meth) acryloyl, (meth) acrylic acid, etc.
Notation has the same meaning. Polyfluoroalkyl group-containing (meth) acrylate (A) is a compound having one (meth) Chestnut <br/> Roiruokishi group and at least one polyfluoroalkyl group.

A polyfluoroalkyl group (hereinafter sometimes referred to as R _f ) is a linear or branched alkyl group having two or more fluorine atoms, and has 1 to 2 carbon atoms.
0 is preferable, and 4 to 16 is more preferable. A polyfluoroalkyl group in which 80% or more of the hydrogen atoms of a normal alkyl group is substituted with a fluorine atom is preferable, and a polyfluoroalkyl group in which all of the hydrogen atoms are substituted with a fluorine atom (that is, a perfluoroalkyl group) ) Is most preferred. In some cases, other atoms other than the fluorine atom (such as a hydrogen atom and a chlorine atom) may be bonded to the carbon atom in a small number, and an oxygen atom may be present between the carbon-carbon bonds. (i.e., it may have a Oh carboxymethyl polyfluoroalkylene group). The perfluoroalkyl group is preferably a linear group, and is represented by C _n F _{2n + 1} (where n is preferably 4 to 16, particularly preferably 6 to 12).

[0009] preferably present binding group between the polyfluoroalkyl group and a (meth) Chestnut <br/> Roiruokishi group, the linking group is other as shown by an alkylene group or the following specific examples 2 Valent linking groups are preferred. The bonding group is not limited to these examples, and various bonding groups known as known polyfluoroalkyl group-containing (meth) acrylates can be employed.

As mentioned above, known compounds can be used as the polyfluoroalkyl group-containing (meth) acrylate (A) in the present invention. In addition, two or more compounds can be used in combination as (A). In particular, the polyfluoroalkyl group-containing (meth) acrylate actually used is often a mixture of two or more compounds having different carbon numbers in the polyfluoroalkyl group portion, and such a mixture is also used in the present invention. It is preferably used.

Hereinafter, specific examples of the polyfluoroalkyl group-containing (meth) acrylate (A) will be shown, but the present invention is not limited thereto.
Not a constant. In the following formula, R ¹ represents a hydrogen atom or a methyl group, R _f represents a polyfluoroalkyl group (especially a perfluoroalkyl group).

CH ₂ = C (R ¹ ) COOCH ₂ CH ₂ R _f CH ₂ = C (R ¹ ) COOCH ₂ CH ₂ N (C ₃ H ₇ ) COR _f CH ₂ = C (R ¹ ) COOCH (CH ₃ ) CH ₂ R _f CH ₂ = C (R ¹ ) COOCH ₂ CH ₂ N (CH ₃ ) SO ₂ R _f CH ₂ = C (R ¹ ) COOCH ₂ CH ₂ N (CH ₃ ) COR _f CH ₂ = C ( R ¹ ) COOCH ₂ CH ₂ N (C ₃ H ₇ ) SO ₂ R _f CH ₂ = C (R ¹ ) COOCH ₂ CH ₂ N (C ₂ H ₅ ) COR _f CH ₂ = C (R ¹ ) COOCH ₂ CH ₂ N (C ₃ H ₇ ) SO ₂ R _f CH ₂ = C (R ¹ ) COOCH (CH ₂ Cl) CH ₂ OCH ₂ CH ₂ N (CH ₃ ) SO ₂ R _f

[0013] (B) in the present invention, a "polypeptide having a urethane bond (meth) acrylate", hereinafter also referred to urethane poly (meth) acrylate. Urethane poly (meth) acrylate (B) is a compound having at least one urethane bond and at least two (meth) acryloyloxy group. Moreover this (B) is preferably free or Not have a blocked isocyanate Na over <br/> preparative group. In the present invention this (B) is cut at a more併.

[0014] The (B) in the present invention, hydroxyl group-containing (meth) acrylate and Poriisoshia Na over preparative Compound (2
Is preferably a reaction product of an organic compound) having the above isocyanate Na over preparative group. In particular, it is preferred that the reaction product of a Poriisoshia Na over preparative compound having one (meth) acrylate having a hydroxyl group and two or three isocyanate Na over preparative group. More preferably (B) is the reaction product of hydroxyalkyl (meth) acrylate and Jiisoshia Na over preparative compounds. This (B) can also be regarded as a polyester of a polyhydroxy compound having a urethane bond and (meth) acrylic acid.

The above hydroxyl group-containing (meth) acrylate is
Mono- and polyhydric alcohols and (meth) acrylic acid - or poly - an ester, a compound having at least one hydroxyl group. Preferably, monoesters of dihydric alcohol and (meth) acrylic acid, in particular mono-esters of alkylene diol and (meth) acrylic acid, i.e., hydroxyalkyl (meth) acrylate, are preferred.
Examples of the alkylene diol include, for example, ethylene glycol, diethylene glycol, propylene glycol,
Examples include dipropylene glycol, butanediol, and hexanediol.

[0016] As the Poriisoshia Na over preparative compounds, aromatic, aliphatic, alicyclic, and other Poriisoshia Na over preparative compounds, and their modified products can be used. Specifically, for example, tolylene diisocyanate,
Diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and trimethylolpropane of these diisocyanate compounds Modified products, modified isocyanurate rings, and adducts with polyhydric alcohols such as glycerin are also available.

[0017] As the (B), a compound represented by the following general formula (1), i.e., having one hydroxyl group (meth)
Reaction products of acrylate and Jiisoshia Na over preparative compound is preferably. [CH ₂ = C (R ¹ ) COOR ² OCONH-] ₂ R ³ (1) Here, R ¹ represents a hydrogen atom or a methyl group, R ² represents a residue obtained by removing a hydroxyl group from a diol, and R ³ represents a residue obtained by removing an isocyanate group from a diisocyanate compound.

In the above formula (1), R ² is preferably an alkylene group having 2 or more carbon atoms or a polyoxyalkylene group, particularly an alkylene group having 2 to 6 carbon atoms or 2 to 6 carbon atoms.
And a polyoxyalkylene group comprising a repetition of the above oxyalkylene group is preferred. R ³ is preferably a residue obtained by removing two isocyanate groups from a diisocyanate compound selected from tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

As the compound (B), a preferable compound after the compound represented by the general formula (1) is one molecule of a modified diisocyanate compound such as a modified trimethylolpropane or a modified isocyanurate ring , and one hydroxyl group. Is a reaction product with three (meth) acrylate molecules having

In the present invention, in the copolymerization of the above (A) and (B), one of monomers having a radically polymerizable unsaturated bond (hereinafter referred to as a copolymerizable monomer) other than these two monomers is used. The above may be copolymerized with (A) and (B). Suitable copolymerizable monomers include, for example, although the following monomers can be exemplified Lena <br/> physician limited thereto. Preferred copolymerizable monomers are vinyl chloride and (meth) acrylates other than the following (A) and (B). Particularly preferred copolymerizable monomers are vinyl chloride and stearyl acrylate.

(Meth) acrylates 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, poly (oxyalkylene) (meth) acrylate, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate ) Acrylate, benzyl (meth) acrylate, isocyanatoethyl (meth) acrylate,
Aziridinyl (meth) acrylate, (meth) acrylate having a polysiloxane chain .

[0022] Other copolymerizable monomers ethylene, butadiene, isoprene, chloroprene, vinyl acetate, vinyl halides such as vinyl fluoride and vinyl chloride, styrene, alpha-methyl styrene, p- methyl styrene, (meth) acrylic acid , (Meth) acrylamide, diacetone (meth) acrylamide, methylolated (meth) acrylamide, N-methylol (meth) acrylamide, vinyl alkyl ether, halogenated alkyl vinyl ether, vinyl alkyl ketone, maleic anhydride, N-vinyl carbazole.

The urethane bond-containing poly (meth) acrylate (B) is used in an amount of 0.1 to 100 parts by weight of all monomers.
10 parts by weight, 0.5 to 5 parts by weight Furthermore, it is preferable to copolymerize. If the amount is less than 0.1 part by weight, the effect of the crosslinking is insufficient and the object of the present invention cannot be achieved. If the amount exceeds 10 parts by weight, the crosslinking becomes excessive this time and conversely high initial performance cannot be obtained. Containing polyfluoroalkyl group (meth)
Acrylate (A) is 100 parts by weight of all the monomers to 40 parts by weight or more, the further 55 parts by weight or more, it is preferable to copolymerize. If this ratio is small, it is difficult to exhibit sufficient water and oil repellency.

The copolymerizable monomers with the same reason, 55 parts by weight or less relative to 100 parts by weight of all the monomers, the further 45
It is preferably not more than part by weight. If the copolymerization of copolymerizable monomers, the lower limit particularly LIMITED Lena Iga,
An effective amount according to the purpose of use (for example, 100
5 parts by weight) is appropriate.

(C) in the present invention is a copolymer obtained by copolymerizing the above (A) and (B), or (A) and (B) and a copolymerizable monomer. This in order to obtain a copolymer can be selected arbitrarily methods and conditions for various polymerization reactions, for example, bulk polymerization, suspension polymerization, emulsion polymerization, radiation polymerization, adoption of various polymerization methods such as photopolymerization kill at.
For Specifically, for example emulsion polymerization, a mixture of monomers is emulsified in water in the presence of such a surfactant, it kills at adopted a method of polymerizing under stirring. The polymerization initiating source, an organic acid peroxide, azo compounds, various polymerization initiators such as persulfates, further adopted such as ionizing radiation, such as γ- line
Kill at. Further, emulsifier, anionic, cationic addition <br/> wear in use nonionic various surfactants.

In the case of performing solution polymerization, for example, the monomer is dissolved in an appropriate organic solvent, and the polymerization is effected by the action of a polymerization initiation source (one that is soluble in the organic solvent used). Suitable solvents for solution polymerization, trichlorotrifluoroethane, tetrachloro difluoroethane, there are chlorine or solvents fluoropolymer such as methyl chloroform, more methyl isobutyl ketone, methyl ethyl ketone, butyl acetate, and ethyl acetate may also be used .

To the obtained copolymer (C)Non-copolymerizableBro
Incorporating cooked polyisocyanate compound (D)
As a result, the water / oil repellent composition of the present invention is obtained.this
Since (D) is a non-copolymerizable compound,
Then, even if this (D) is present in the polymerization system to carry out the polymerization,
Good. For copolymer (C)Non-copolymerizableBlocked
The amount of the lysocyanate compound (D) is particularly limited.Without,
Achieve the intended purpose even in small quantitiesInWearBut, Copolymer
0.1% by weight or more, particularly 1% by weight or more, based on (C)
Preferably, there is. Upper limit is particularly limitedRenaBut 10
A suitable amount is about weight%.

(D) in the present invention is a non-copolymerizable blocked polyisocyanate compound, which has one or more, preferably two or more isocyanate groups blocked with a blocking agent. Compounds. This (D) is an isocyanate group-containing prepolymer obtained by reacting the above-mentioned polyisocyanate compound or a modified product thereof, or an excess thereof with a polyol, and the like. Obtained by blocking.

As the polyisocyanate compound, specifically, the above-mentioned specific compounds, particularly diisocyanate compounds, are preferred. The blocking agent, kill <br/> known blocking agent capable of blocking the isocyanate group in use. Preferred specific examples include oximes, phenols, β-diketones, malonic esters, lactams, and the like. In particular, alkylketoximes are preferred from the viewpoint of decomposition temperature.

This (D ) is preferably a compound represented by the following general formula (2), which is a diisocyanate compound blocked with an alkyl ketoxime.

[R ⁵ R ⁴ C = N-OCONH-] ₂ R ³ (2) Here, R ³ represents a residue obtained by removing an isocyanate group from a diisocyanate compound, and R ⁴ and R ⁵ each represent a lower alkyl group.

In the general formula (2), R ³ represents two isocyanate groups from a diisocyanate compound selected from tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate. Is preferably a residue excluding. A lower alkyl group as R ⁴ and R ⁵ is
It is preferably an alkyl group having 1 to 4 carbon atoms.

The water / oil repellent composition of the present invention is prepared in an arbitrary form such as an emulsion, a solvent solution or an aerosol according to a conventional method. For example, an aqueous emulsion type composition is prepared by the emulsion polymerization method as described above, and a solvent solution type composition is prepared by solution polymerization.

The water / oil repellent composition of the present invention is applied to the article to be treated by an arbitrary method according to the kind of the article to be treated and the preparation form. For example, when an aqueous emulsion or a solvent solution, and drying is deposited on the surface of the object to be treated <br/> object article is adopted by the cladding method such as dip coating. If necessary, curing may be performed. Further, the water- and oil-repellent composition of the present invention may contain other additional components. For example, other water and oil repellents, cross-linking agents,
Insect repellents, flame retardants, antistatic agents, Ru can be appropriately added in combination of additives such as anti-wrinkle agent.

The articles that can be treated with the water / oil repellent composition of the present invention are not particularly limited. For example, textile fabrics, textile knits, leather, and fur. As textile fibers and textile fabrics,
Animal and plant natural fibers such as cotton, hemp, wool, silk, polyamide,
Examples include synthetic fibers such as polyester, polyvinyl alcohol, polyacrylonitrile, polyvinyl chloride, and polypropylene; semi-synthetic fibers such as rayon and acetate; and woven or knitted fabrics of mixed fibers thereof.

[0036] is a more detailed description of the present invention through examples and so on below, the present invention is Lena <br/> physician limited to these examples.

[0037]

EXAMPLES The evaluation of water repellency and oil repellency shown in the following Examples was evaluated by the following evaluation tests. Water repellency: Expressed by a water repellency number (see Table 1) by a spray method according to JIS L-1092. Oil repellency: Several drops (approximately 4 mm in diameter) of the test solution shown in Table 2 were placed at two places on the test cloth, and discrimination was made based on the permeation state after 30 seconds (AATCC-TM118-1966).

The following water repellent Nos. And oil repellency No.
The results of the evaluation, which are indicated by adding a + mark to the
o. It is slightly better than that represented by.

[0039]

[Table 1]

[0040]

[Table 2]

[0041] [Example 1] in the thermocouple type thermometer and electric-acting glass autoclave with a stirrer was attached (1-liter), (hereinafter referred to as FA) perfluoroalkyl acrylate 60 parts by weight, DMA ( a) 1.5 parts by weight, BISO (a) 1.5
Parts, EHMA37 parts, 5 parts by weight of polyoxyethylene lauryl ether, stearyl trimethyl ammonium chloride Li de 1 part by weight, 60 parts by weight of acetone, water 175
Parts by weight, and 0.5 part by weight of an initiator (a) for polymerization, and after performing nitrogen replacement with stirring for about 20 minutes,
The temperature was raised to 60 ° C. to initiate polymerization. After stirring at 60 ° C. for 15 hours, the mixture was cooled to obtain an emulsion having a solid content of 31% by weight.

The conversion of the copolymerization reaction by gas chromatography was 99.0 to 99.8% (based on the polyfluoroalkyl group-containing monomer compound). Further, the yield of the stable emulsion emulsion based on all monomers is 95 to
It was 99%.

The abbreviated compounds are as follows. The starting compounds used in the following Examples 2 and Comparative Examples are also shown below. _{FA; R f CH 2 CH 2} OCOCH = CH 2, R f is an average of about 9 perfluoroalkyl group charcoal <br/> prime. DMA (a): reaction product of one molecule of hexamethylene diisocyanate and two molecules of 2-hydroxyethyl methacrylate. DMA (b): reaction product of one molecule of diphenylmethane diisocyanate and two molecules of 2-hydroxyethyl methacrylate.

BISO (a): reaction product of one molecule of hexamethylene diisocyanate and two molecules of methyl ethyl ketoxime. BISO (b); diphenylmethane diisocyanate 1
Reaction product of a molecule with two molecules of methyl ethyl ketoxime. BISO (C): reaction product of one molecule of isocyanurate ring-modified hexamethylene diisocyanate and three molecules of methyl ethyl ketoxime. Initiator (a): azobis (dimethyleneisobutyramide), <product name of VA-06, manufactured by Wako Pure Chemical Industries, Ltd.
1 "> Initiator (b); 2,2'-azobis (2-amidinopropane) dihydrochloride, <Wako Pure Chemical Industries, Ltd., trade name" V "
-50 ">.

EHMA; 2-ethylhexyl methacrylate. StMA: stearyl acrylate. VC: vinyl chloride. AIBN; azobis (isobutyronitrile).

[0046] [Example 2] in thermocouple thermometer electrostatic-acting glass autoclave with a stirrer was attached (1-liter), FA60 parts,
DMA (a) 1.5 parts by weight, BISO (a) 1.5 parts by weight, EHMA37 parts, 1,1,1-trichloro b ethanone <br/> emissions 233 parts by weight, and AIBN3 part by weight, stirring After performing nitrogen replacement for about 20 minutes while heating, the temperature was raised to 60 ° C. to initiate polymerization. After stirring at 60 ° C. for 20 hours, the mixture was cooled to obtain a pale yellow solution having a solid content of 31% by weight.
The conversion of the copolymerization reaction by gas chromatography was 9
9.0 to 99.8% (based on the polyfluoroalkyl group-containing monomer compound).

[0047] In Example 3, 4] In the same manner as in Example 1, a monomer, a polymerization initiator, a non-co
Emulsion polymerization was performed by changing the polymerizable blocked polyisocyanate compound and the like. Table 3 shows the raw material combinations used.
Table 4 shows the polymerization initiator and the polymerization conditions. Table 3
Parts are parts by weight, and so on.

[0048] In Examples 5 and 6] In the same manner as in Example 2, a monomer, a polymerization initiator, a non-co
Solution polymerization was performed by changing the polymerizable blocked polyisocyanate compound and the like. Table 3 shows the raw material combinations used.
Table 4 shows the polymerization initiator and the polymerization conditions.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that no non-copolymerizable blocked polyisocyanate compound was contained, to obtain an emulsion having a solid content of 30% by weight. Table 3 shows the combinations of the raw materials used, and Table 4 shows the polymerization initiator and the polymerization conditions.

Comparative Example 2 A light yellow solution having a solid content of 30% by weight was obtained by polymerization in the same manner as in Example 2 except that no non-copolymerizable blocked polyisocyanate compound was contained. Table 3 shows the combinations of the raw materials used, and Table 4 shows the polymerization initiator and the polymerization conditions.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 1 except that dimethacrylate having a urethane bond was not used, to obtain an emulsion having a solid content of 30% by weight. Table 3 shows the combinations of the raw materials used, and Table 4 shows the polymerization initiator and the polymerization conditions.

Comparative Example 4 A pale yellow solution having a solid content of 30% by weight was obtained by polymerization in the same manner as in Example 2 except that dimethacrylate having a urethane bond was not used. Table 3 shows the combinations of the raw materials used, and Table 4 shows the polymerization initiator and the polymerization conditions.

[0053]

[Table 3]

[0054]

[Table 4]

The solid concentration of the emulsion polymerization emulsion obtained by the above method was adjusted to 20% by weight to prepare a latex stock solution, and this stock solution was diluted with water (the ratio of the stock solution to water was 1.5% by weight). ) A latex treatment liquid was prepared.
The water / oil repellency was measured using this latex treatment liquid. On the other hand, the solution obtained by the solution polymerization is 1,1,1
A solid solution concentration of 20% by weight with trichloroethane to obtain a stock solution, which is further diluted with 1,1,1-trichloroethane (the ratio of the stock solution to the solvent is 1.5%);
% By weight) Water / oil repellency was measured.

The test was performed on a nylon taffeta cloth, and the water / oil repellency treatment was performed as follows. That is, the latex treating solution or diluted as described were immersed test cloth 1,1,1-trichloroethane solution, two squeeze the fabric between the rubber roller and the wet pick-up of 30 wt%. Next, it is dried at 110 ° C. for 90 seconds, and further dried for 17 seconds.
Heat treatment was performed at 0 ° C. for 60 seconds. Washing durability (HL-5) was repeated 5 times according to JIS L-0217103 method, dried at 100 ° C. for 3 minutes, and subjected to a test. Table 5 shows the results of measuring the water and oil repellency of the test cloths thus obtained.
Are shown together.

[0057]

[Table 5]

[0058]

According to the present invention, a copolymer (C) having good water / oil repellency is obtained.
Non-copolymerizable blocked polyisocyanate compound (D)
By blending the above, an excellent water / oil repellent composition capable of exhibiting high durability which could not be achieved conventionally was obtained.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI D06M 15/263 D06M 15/263 (58) Investigated field (Int. Cl. ⁷ , DB name) C09K 3/18 C08G 18/62 C08L 33/16 D06M 13/395-13/398 D06M 15/263-15/277

Claims (5)

(57) [Claims] (1) A (meth) having a polyfluoroalkyl group
Poly (main with A acrylate (A) and urethane bond
Data) A acrylate (B) as essential components and at least the two monomers copolymerized with the copolymer obtained (C),
And a water / oil repellent composition containing a non-copolymerizable blocked polyisocyanate compound (D). 2. The copolymer (C) comprises the (meth) acryle
Is over preparative (A) and the poly (meth) acrylate (B) and further co Polymerization obtained by copolymerizing vinyl chloride or stearyl acrylate, water and oil repellent composition according to claim 1. Wherein the said (meth) acrylate (A) port
Li (meth) the acrylate (B) blocked polyisocyanate compound (D) obtained by polymerizing in the coexistence,
The water / oil repellent composition according to claim 1. Wherein said poly (meth) acrylate (B) is,
A compound represented by the following general formula (1) :
4. The water / oil repellent composition according to 2 or 3 . [CH ₂ = C (R ¹ ) COOR ² OCONH-] ₂ R ³ (1) Here, R ¹ represents a hydrogen atom or a methyl group, R ² represents a residue obtained by removing a hydroxyl group from a diol, and R ³ represents a residue obtained by removing an isocyanate group from a diisocyanate compound. 5. The blocked polyisocyanate compound (D) is a compound represented by the following general formula (2):
The water / oil repellent composition according to claim 1 , 2, 3, or 4 . [R ⁵ R ⁴ C = N-OCONH-] ₂ R ³ (2) Here, R ³ represents a residue obtained by removing an isocyanate group from a diisocyanate compound, and R ⁴ and R ⁵ each represent a lower alkyl group.