JPH041765B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing thermoplastic polyurethane resin, and more specifically, it is soluble in general-purpose organic solvents, has excellent mechanical properties in itself, and has excellent heat resistance when cured into a three-dimensional network. The object of the present invention is to provide a method for producing a thermoplastic polyurethane resin which can provide a polyurethane resin having solvent resistance and is particularly suitable for the fields of paints, coating agents, adhesives, etc. Polyurethane resins have excellent physical properties such as toughness and abrasion resistance that are unique to polyurethane resins due to intermolecular hydrogen bonds formed by urethane bonds. However, increasing the urethane group concentration lowers the solubility in general-purpose organic solvents. That is, conventional thermoplastic polyurethane resins are either insoluble in general-purpose organic solvents, or highly polar and high-boiling solvents such as dimethylformamide, N-methylpyrrolidone, dimethylsulfamide, diclohexane, tetrahydrofuran,
Many of them are soluble only in cyclic ethers such as dioxane, and when used as a solution in such an organic solvent, there are problems such as decreased workability and swelling or dissolution of the material to be coated. In addition, in order to improve the heat resistance, solvent resistance, etc. of high molecular weight thermoplastic polyurethane resins, polyisocyanate compounds are used in the case of hydroxyl-terminated thermoplastic polyurethane resins, and polyols are used in the case of isocyanate-terminated thermoplastic polyurethane resins. A so-called two-component method is known in which a curing reaction is performed using a compound. However, in the case of conventional thermoplastic polyurethane resins that use terminal groups as crosslinking points, crosslinking by urethane bonds has a low crosslinking density, so it is not possible to sufficiently improve heat resistance.
No improvement in solvent resistance can be obtained. Further, crosslinking by allophanatization reaction, which is a reaction between a urethane bond and an isocyanate group, has the drawback of requiring high temperature. In order to improve the crosslinking density of the cured product obtained by the two-component method, branched polyurethane resin is created by using tri- or higher-functional polyol components such as trimethylolpropane (TMP) and pentaerythol as part of the raw materials for polyurethane resin. is known to be used. This method has the disadvantage that the solubility of the polyurethane resin in general-purpose solvents decreases or becomes insolubilized depending on the amount of the trifunctional or higher-functional polyol component used, and the pot life in the two-component state decreases. The present inventors have arrived at the present invention as a result of intensive research to solve the above-mentioned drawbacks and develop a thermoplastic polyurethane resin having the characteristics shown below. It is soluble in at least one solvent selected from methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, cellulosolve acetate, toluene, xylene, and the like. Excellent mechanical properties such as toughness and wear resistance. When used in a two-component method, it has a long pot life and excellent curability. The objects of the present invention are long chain diols, short chain diols,
It has been found that this can be achieved by using an isocyanurate ring-containing triisocyanate together with an organic diisocyanate, and by using a branched short-chain diol as the short-chain diol within a specific range. That is, the present invention uses long chain diols with a molecular weight of 500 to 5000.
A method for producing a thermoplastic polyurethane resin using (A), a short-chain diol (B) with a molecular weight of less than 500, an organic diisocyanate (C), and an isocyanurate ring-containing triisocyanate (D), the method comprising Contains 30 to 100% by weight of a short chain diol having an alkyl group in the chain based on the total weight of component (B), and the above (A), (B),
This is a method for producing a thermoplastic polyurethane resin having a molecular weight of 8,000 or more, which is characterized by reacting components (C) and (D) in the following ratio. () 1≦b/a≦5 () 5×10 ^-3 ≦d/c+d≦1×10 ^-1 () 0.9≦a+b/c+d≦1.3 (where a is the number of moles of component (A), b is the number of moles of component (B), c is the number of moles of component (C), and d is the number of moles of component (D).) In the present invention, isocyanurate ring-containing as part of the polyisocyanate raw material By using triisocyanate in a specific range, a thermoplastic polyurethane resin with excellent curability can be obtained without significantly shortening the pot life in the two-component method. Even if this isocyanurate ring-containing triisocyanate is replaced with another trifunctional raw material, such as trimethylolpropane or a 1:3 adduct of trimethylolpropane and tolylene diisocyanate, the effects found in the present invention are not obtained. The long chain diol (A) used in the present invention has a molecular weight of
ranges from 500 to 5000, polyester diol,
Examples include polyether diol and polycarbonate diol. The carboxylic acid component of polyester diol includes aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalic acid, β-oxybenzoic acid, p-
Examples include aromatic oxycarboxylic acids such as (hydroxyethoxy)benzoic acid, aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid. Particularly preferred are terephthalic acid, isophthalic acid, adipic acid, and sebacic acid. In addition, the glycol components of polyester diol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-
pentanediol, 1,6-hexanediol,
Neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, cyclohexanedimethanol, ethylene oxide adduct and propylene oxide adduct of bisphenol A, ethylene of hydrogenated bisphenol A oxide adducts and propylene oxide adducts,
Examples include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Raw materials for polyester diol other than those listed above include 5-sodium sulfoisophthalic acid, 5-
Ester-forming compounds containing sulfonic acid metal bases such as potassium sulfoisophthalic acid and sodium sulfoterephthalic acid, and the following general formula [],
It may also be a polyester diol copolymerized with a phosphorus-containing ester-forming compound shown in [ ]. (In the formula, R is a monovalent ester-forming functional group. R ₂ and R ₃ are the same or different groups, and are a monovalent hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, and a monovalent ester-forming functional group. selected from the group consisting of ester-forming functional groups.X represents a divalent or trivalent organic residue; _n1 is 1 or 2; _n2 and _n3 are each 0
or an integer from 1 to 4) (In the formula, R ₄ is a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms that may contain an ester-forming functional group, or M ₂ . _{R 5} is a divalent or trivalent group having 1 to 6 carbon atoms.
valent hydrocarbon group. R ₆ is a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group, or M ₃ . M ₁ , M ₂ and M ₃ are alkali metal atoms. m represents an integer of 0 or 1, l represents an integer of 1 or 2) A phosphorus-containing compound represented by the general formula [], [],
Thermoplastic polyurethane resins using polyester diols obtained as at least one raw material containing compounds containing sulfonic acid metal bases have a low ability to disperse inorganic pigments, fillers, etc. that are found in conventionally known thermoplastic polyurethane resins. This is effective in significantly improving this drawback. Examples of polyether diols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. The polycarbonate diol is a long chain diol represented by the general formula H(-O-R-OCO) _-o ROH, where R is diethylene glycol, 1,6-hexanediol,
Bisphenol A and the like. The long chain diol (A) used in the present invention has a molecular weight of
Use something between 500 and 5000. If the molecular weight is less than 500, the urethane group concentration will increase, reducing the flexibility of the resin.
Solvent solubility decreases. Moreover, when the molecular weight exceeds 5000, the urethane group concentration decreases, and the toughness, abrasion resistance, etc. characteristic of polyurethane resins decrease. The short chain diol (B) used in the present invention has a molecular weight of
less than 500, ethylene glycol, 1,3-
Straight chain glycols such as propylene glycol, 1,4-tetramethylene glycol, 1,6-hexanediol, cyclohexanedimethanol, xylylene diglycol, ethylene oxide adduct of bisphenol A, propylene glycol,
Neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 2,2,4-trimethyl-1,3-pentanediol, propylene oxide adduct of bisphenol A, neopentyl hydroxypivalate, stearic acid Examples include branched glycols such as monoglycerides. Examples of short chain diols (B) other than those mentioned above include phosphorus-containing compounds represented by the following general formula []. (In the formula, R ₇ and R ₈ represent a monovalent hydrocarbon group,
They may be the same or different groups. R ₉ and R ₁₀ are substituted or unsubstituted divalent alkylene groups, oxyalkylene groups or polyoxyalkylene groups, and may be the same or different groups. Y, Z
is a hydroxyl group when R ₉ and R ₁₀ are alkylene groups,
When R ₉ and R ₁₀ are an oxyalkylene group or a polyoxyalkylene group, they represent a hydrogen atom. ) When a phosphorus-containing compound represented by the general formula [] is used as a raw material for a thermoplastic polyurethane resin, it is effective in improving the low dispersibility of inorganic pigments, fillers, etc., which is a drawback of conventional polyurethane resins. In the present invention, 30 to 100% by weight of branched glycol is used in the short chain diol (B) component to impart solubility in general purpose solvents. Although it depends on the manufacturing method of thermoplastic polyurethane resin, the ratio of short chain diol, etc., diol having a side chain alkyl group accounts for 30% by weight.
If it is less than that, solubility will decrease. The organic diisocyanate (C) used in the present invention includes 2,4-tolylene diisocyanate, 2,6
-tolylene diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate, m-phenylene diisocyanate, hexamethylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 2,
4-naphthalene diisocyanate, tetramethylene diisocyanate, 3,3'-dimethyl-4,
4'-biphenylene diisocyanate, 4,4'-diphenylene diisocyanate, 4,4'-diisocyanate-diphenyl ether, 1,5-naphthalene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate,
Examples include 1,3-diisocyanatemethylcyclohexane, 1,4-diisocyanatemethylcyclohexane, 4,4'-diisocyanatedicyclohexane, 4,4'-diisocyanatedicyclohexylmethane, and isophorone diisocyanate. Examples of the isocyanurate ring-containing triisocyanate used in the present invention include trimers of the above-mentioned organic diisocyanates and polymers of the trimers. Examples of isocyanurate ring-containing triisocyanates obtained from 2,4-tolylene diisocyanate include: For example, the following can be mentioned. Examples of the short chain diol having an alkyl group in the side chain used as a raw material for the thermoplastic polyurethane resin of the present invention include 1,2-propylene glycol,
Examples include 1,3-butanediol neopentyl glycol, an ethylene oxide adduct or a propylene oxide adduct of bisphenol A. The resin contains a long chain diol (A) with a molecular weight of 500 to 5000, a short chain diol (B) with a molecular weight of less than 500, an organic diisocyanate (C), and an isocyanurate ring-containing triisocyanate (D), with the number of moles of each component being determined. a,
When b, c and d, () 1≦b/a≦5 () 5×10 ^-3 ≦d/c+d≦1×10 ^-1 () Polyaddition reaction in the range of 0.9≦a+b/c+d≦1.3 It can be obtained by
When b/a exceeds 5, the solubility in general-purpose solvents decreases, and when b/a is less than 1, the toughness characteristic of polyurethane resins decreases, making it impossible to achieve the object of the present invention.
d/c+d represents the proportion of isocyanurate ring-containing triisocyanate in the isocyanate component,
When d/c+d exceeds 1×10 ⁻¹ , the polyurethane resin gels. On the other hand, if d/c+d is less than 5×10 ⁻³ , the effect of using the isocyanurate ring-containing triisocyanate will not be seen. a+b/c+d determines the molecular weight of the thermoplastic polyurethane resin.
When a+b/c+d is less than 1, the resin becomes an isocyanate-terminated polyurethane resin and is cured by moisture. In the present invention, a+b/c+d is desirably 1 or more from the viewpoint of storage stability in a solution state. Methods for producing thermoplastic polyurethane resins include the one-shot method in which all diol components and all isocyanate components are reacted simultaneously, and the one-shot method in which a long-chain diol and an isocyanate component are reacted to obtain an isocyanate-terminated prepolymer that is chain-extended with a short-chain diol. There is a polymer method. In the present invention, in either the one-shot method or the prepolymer method, especially organic diisocyanates with 70%
It is preferable to add the isocyanurate ring-containing triisocyanate at the stage where % or more of the isocyanurate ring-containing triisocyanate has reacted. When the isocyanurate ring-containing triisocyanate is added during a reaction in which the organic diisocyanate content is less than 70%, gelation may occur if the amount of the isocyanurate ring-containing triisocyanate used is large. Thermoplastic polyurethane resins can be produced by using raw materials in a molten state or by dissolving them in a solvent, but in the case of the present invention, the entire reaction is carried out in a single or mixed solvent such as methyl ethyl ketone, toluene, or ethyl acetate. Preferred is a method in which the prepolymer is prepared in a molten state and the chain extension reaction is carried out in a solvent. The molecular weight of the thermoplastic polyurethane resin needs to be 8000 or more in view of mechanical properties such as toughness and abrasion resistance. When producing a thermoplastic polyurethane resin, stannous octylate, dibutyltin dilaurate, triethylamine, etc. may be used as a reaction catalyst. Also,
Ultraviolet absorbers, hydrolysis inhibitors, antioxidants, gas yellowing inhibitors, colorants, inorganic fine particles, metal soaps, organopolysiloxanes, perfluoroalkyl group-containing mold release agents, and other additives are added to thermoplastic polyurethane resins. It may be added before, during or after the production. The thermoplastic polyurethane resin thus obtained is suitable for use in paints, coating agents, adhesives, etc., and is also useful as a fiber treatment agent, magnetic binder, etc. Hereinafter, the present invention will be specifically explained with reference to Examples. In addition, in the examples, parts simply indicate parts by weight. <Production example of polyester resin> 175 parts of dimethyl terephthalate,
Add 78 parts of dimethyl isophthalate, 161 parts of ethylene glycol, 145 parts of neopentyl glycol, 14.8 parts of dimethyl 5-sodium sulfoisophthalate, and 0.2 parts of tetrabutyl titanate.
Transesterification reaction was carried out at 220°C for 4 hours. Next, 131 parts of sebacic acid was added and the mixture was reacted at 210 to 230°C for 1 hour, followed by polycondensation reaction at 230°C for 20 minutes while reducing the pressure of the reaction system to 1 to 0.2 mmHg. The obtained polyester diol (A-1) was found to have a molecular weight of 2000 and an acid value by end titration method, NMR analysis, etc.
The content was 0.2KOHmg/g, and the composition was as follows. Terephthalic acid 45 mol% Isophthalic acid 20 Sebacic acid 32.5 5-Sodium sulfoisophthalic acid 2.5 Ethylene glycol 50 Neopentyl glycol 50 Polyester diols (A-2) to (A-5) shown in Table 1 were produced by the same manufacturing method. Obtained. Example 1 172 parts of toluene and 172 parts of methyl ethyl ketone were placed in a reaction vessel equipped with a thermometer, stirrer, and reflux condenser.
After dissolving 100 parts of polyester diol (A-1) and 10 parts of neopentyl glycol, 32 parts of 4,4'-diphenylmethane diisocyanate and 0.02 parts of dibutyltin dilaurate were added.
After reacting at ~75°C for 60 minutes, 10 parts of Coronate 2030 (manufactured by Nippon Polyurethane Co., Ltd., 50% solution of tolylene diisocyanate trimer) was added, and the mixture was further incubated at 75°C.
The reaction was allowed to proceed for 10 hours. The obtained polyurethane resin (U-1) solution was a pale yellow, transparent solution with a solution viscosity of 30 poise/25°C and a solid content concentration of 30% by weight. Furthermore, analysis by gel permeation chromatography (GPC) showed that the molecular weight of the polyurethane resin was 18,000. Examples 2 to 6, Comparative Examples 1 to 9 Polyurethane resins (U-2) to (U-14) shown in Table 2 were obtained in the same manner as in Example 1. During the comparison, Comparative Example 1 was a resin containing no isocyanurate ring-containing triisocyanate, and Comparative Examples 2 and 3 were resins containing 5× isocyanurate ring-containing triisocyanate.
The resin does not satisfy the range of 10 ^-3 ≦d/c+d≦1×10 ^-1 . Comparative Examples 4 and 5 use triisocyanate containing no isocyanurate ring and TMP (trimethylolpropane). In addition, Comparative Examples 6 and 7 are outside the range of 1≦b/a≦5, and Comparative Example 6 with b/a<1 has extremely high breaking strength as shown in the resin properties in Table 2. It does not have the desired toughness of polyurethane resin. In Comparative Example 7 where b/a>5, the solution also becomes cloudy. In Comparative Example 8, the amount of branched short-chain diol was less than 30% by weight as a short-chain diol component, resulting in cloudiness. In Comparative Example 9, the polyurethane resin has a molecular weight of less than 8000, and its resin properties are significantly lower than the toughness of the polyurethane resin targeted by the present invention.

【table】

【table】

【table】

[Table] () Curability and thickening in solution A trifunctional isocyanate compound (manufactured by Nippon Polyurethane Kogyo Co., Ltd., Coronate L (TMP) was added to the thermoplastic polyurethane resin solution shown in Table 2.
[TDI] ₃ )) was added at 10% by weight based on the solid content,
The solid content concentration was adjusted to 15% by weight with MEK/toluene = 1/1. This solution was applied to a polyester film so that the film thickness after drying was 10μ, and after drying with hot air at 100℃ for 1 minute, the solution was heated to 40% at 50℃.
It was left in an RH atmosphere for 1 day. The obtained polyester film was immersed in MEK for 1 hour,
The MEK insoluble content was measured by comparing the weight before and after dipping and after completely scraping off the coated layer. Furthermore, Table 3 shows the measurement results of the change in solution viscosity over time of the 15% by weight solution at 20°C.

[Table] * Number of days it took for the solution viscosity to become three times its initial value * Number of days it took for the solution viscosity to become three times its initial value Examples 1 to 6 were compared to the comparative example. It had excellent curability, and there was almost no difference in solution storage stability. () Abrasion resistance A Taber tester was used to measure the amount of wear on a sample under the same conditions as the sample used for measuring the MEK insoluble content in () (however, the film thickness was 50 μm). The results are shown in Table 4.

[Table] () Characteristics of coating film containing pigments and fillers Polyurethane resin/γ-Fe ₂ O ₃ / Hardening agent (Coronate L) / MEK / Toluene = 100 /
100/20/600/600 (weight ratio) Polyurethane resin/Carbon Black/Curing agent (Coronate L)/MEK/Toluene =
100/100/20/600/600 (weight ratio) Mixed in the above ratio, dispersed in a ball mill for 10 hours, coated on a polyester film to a thickness of 10μ, and heated at 100°C.
After drying with hot air for a minute, it was left in an atmosphere of 50° C. and 80% RH for one day. Table 5 shows the measurement results of the curability and surface gloss of the resulting coating film.

[Table] Number of times until taken
*2) Value measured using a gloss meter (data at an incident angle of 60 degrees)
From Table 5, it is clear that the Examples are superior to the Comparative Examples in terms of the curability of the coating film, and the Examples containing polar groups also show high values in terms of surface gloss, which is a measure of pigment dispersibility. ing. () Adhesiveness to polyester film A 50 μm biaxially oriented polyethylene terephthalate film was coated with the same solution blended in () above so that the film thickness after drying was 10 μm, and after drying with hot air at 100°C for 3 minutes, Aluminum foil (15μ
m) under the conditions of 120°C, 3Kg/cm ² , 5sec, and left at 40°C for 3 days. 20℃ and 100℃ of this
Table 6 shows the measurement results of peel strength at ℃.

[Table] From Table 6, it can be seen that the examples are superior in heat resistance compared to the comparative examples. Example 7 In a reaction vessel similar to Example 1, 174 parts of toluene,
After charging and dissolving 174 parts of methyl ethyl ketone, 100 parts of polyester diol (A-1) and 4 parts of propylene glycol, 34 parts of 4,4'-diphenylmethane diisocyanate and 0.02 parts of dibutyltin dilaurate were added and reacted at 70 to 75°C for 60 minutes. After letting
6 parts of 1,6-hexanediol were added, and 30 minutes later, 5 parts of Coronate EH (manufactured by Nippon Polyurethane Kogyo Co., Ltd., a trimer of hexamethylene diisocyanate) was added, and the mixture was further reacted at 75°C for 10 hours. The obtained polyurethane resin (U-15) solution was a pale yellow, transparent solution with a solution viscosity of 15 poise/25°C and a solid content concentration of 30% by weight. The molecular weight of polyurethane resin is
According to GPC analysis, it was 25,000. Example 8, Comparative Examples 10 and 11 Polyurethane resin (U-16) to (U-18) solutions as shown in Table 7 were obtained in the same manner as in Example 7. Comparative Examples 10 and 11 have poor transparency. The reason for this is that the short chain diol component having a side chain alkyl group is less than 30% by weight.

【table】

【table】

Claims (1)

[Claims] 1. Heat treatment using a long chain diol (A) with a molecular weight of 500 to 5000, a short chain diol (B) with a molecular weight of less than 500, an organic diisocyanate (C) and an isocyanurate ring-containing triisocyanate (D) A method for producing a plastic polyurethane resin, which comprises adding a short chain diol having an alkyl group in the side chain as the component (B) to the total weight of the component (B).
Contains 30 to 100% by weight, and the above (A), (B), (C) and
A method for producing a thermoplastic polyurethane resin having a molecular weight of 8,000 or more, characterized by reacting component (D) in the following ratio. () 1≦b/a≦5 () 5×10 ^-3 ≦d/c+d≦1×10 ^-1 () 0.9≦a+b/c+d≦1.3 (where a is the number of moles of component (A), b is the number of moles of component (B), c is the number of moles of component (C), and d is the number of moles of component (D).)