JP2008174761A - Polyurethane resin with novel polyol - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyurethane resin having low hardness and yet exerting high strength and high elongation characteristics. <P>SOLUTION: This manufacturing method of a polyurethane resin is a manufacturing method of a polyurethane resin by reacting a polyol and a polyisocyanate compound, and uses a lactone type polyol which can be obtained by reacting a polyoxyalkylene polyol (A) having (1) a hydroxyl value of 5-30 and (2) a total unsaturation degree of not higher than 0.07 and a lactone, at least as a part of the polyol. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a polyurethane resin exhibiting low hardness, high strength, and high elongation.

Polyurethane resin is obtained by reacting a curing agent with an isocyanate group-terminated polyurethane prepolymer obtained by reacting a high molecular weight polyol such as polyoxyalkylene polyol such as polyoxytetramethylene diol or polyoxypropylene polyol or a polyester polyol with an isocyanate compound. Manufacturing methods are known.
Polyurethane resins produced using polyoxytetramethylene polyol and a polyisocyanate compound as raw materials have been used for applications such as spandex because of their excellent elongation, impact resilience, water resistance, and the like.
However, it is susceptible to oxidative degradation and has the disadvantages of being inferior in weather resistance, heat resistance, elastic recovery at low temperatures, and dyeability. Further, the molecular weight of the raw material polyol was 4000 in terms of viscosity, so that the hardness of the polyurethane resin that can be produced had a lower limit.

  On the other hand, a polyurethane resin produced using a polyester polyol and a polyisocyanate compound as raw materials has excellent elongation and impact resilience, but has a drawback of poor water resistance.

  In order to improve the above, an attempt has been made to produce a polyurethane resin using a polyether polylactone polyol obtained by reacting a lactone with a polyoxypropylene polyol having a molecular weight of about 2000 (see, for example, Patent Document 1).

According to the above proposal, a polyurethane resin having a high elongation and a high elastic recovery rate was obtained. However, since the molecular weight of the raw material polyol was limited, it was difficult to obtain a low-hardness polyurethane resin. Thus, a polyurethane resin having both low hardness, high strength, and high elongation is desired.
JP 58-59213 A

  An object of the present invention is to provide a polyurethane resin that has low hardness and exhibits high strength and high elongation characteristics.

The first feature of the present invention is that, in the method for producing a polyurethane resin by reacting a polyol and a polyisocyanate compound, (1) a hydroxyl value of 5 to 30 and (2) a total unsaturation degree as at least a part of the polyol. The gist of the present invention is a method for producing a polyurethane resin using a lactone-based polyol obtained by reacting a polyoxyalkylene polyol (A) having a ratio of 0.07 or less with a lactone.
According to a second aspect of the present invention, in the method for producing a polyurethane resin by reacting an isocyanate group-terminated prepolymer obtained by reacting a polyol with a polyisocyanate compound and a curing agent, A summary of a method for producing a polyurethane resin using a lactone-based polyol obtained by reacting a lactone with a polyoxyalkylene polyol (A) having a hydroxyl value of 5 to 30 and (2) a total unsaturation of 0.07 or less. To do.

  According to the present invention, a polyurethane resin having a low hardness and exhibiting high strength and high elongation characteristics can be obtained.

(Polyol)
In the present invention, as at least a part of the polyol, a lactone obtained by reacting (1) a hydroxyl value of 5 to 30 and (2) a polyoxyalkylene polyol (A) having a total unsaturation of 0.07 or less with a lactone A system polyol is used. The polyoxyalkylene polyol (A) preferably has 2 to 8 hydroxyl groups obtained by reacting an alkylene oxide in the presence of an initiator and a catalyst.

  As the initiator, a compound having 2 to 8 active hydrogen atoms can be used. Specifically, dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, Trihydric alcohols such as methylolpropane, trimethylolethane and glycerin, tetrahydric alcohols such as pentaerythritol; hexahydric alcohols such as sorbitol and dipentaerythritol, octahydric alcohols such as tripentaerythritol and sucrose, ethylenediamine, hexamethylenediamine , Diamines such as tolylenediamine, alkanolamines such as monoethanolamine, propanolamine, diethanolamine, phenols such as bisphenol A, and a small amount of alkyl in these compounds. Such as relatively low molecular weight of the alkylene oxide adduct obtained by adding a N'okishido the like. A dihydric alcohol or a trihydric alcohol is preferred.

  Examples of the alkylene oxide include propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, and ethylene oxide. Propylene oxide or a combination of propylene oxide and another alkylene oxide is preferable. Only propylene oxide is preferred. Among the alkylene oxides, 70% by mass or more, particularly 90% by mass or more is preferably propylene oxide.

  As the catalyst, a known catalyst can be used. In order to obtain a polyoxyalkylene polyol having a total unsaturation of 0.07 or less, a double metal cyanide complex catalyst, a cesium catalyst, a metal porphyrin catalyst, a phosphazene catalyst, etc. Is preferred. In the present invention, it is particularly preferable to use a double metal cyanide complex. Of these, a complex mainly composed of zinc hexacyanocobaltate is preferable, and an ether and / or alcohol complex thereof is particularly preferable.

  The total degree of unsaturation of the polyol (A) is 0.07 or less, and preferably 0.04 or less. When the total degree of unsaturation is higher than this, an increase in residual tack or a decrease in strength occurs in the resulting polyurethane resin. The hydroxyl value of the polyol (A) is 5-30. When the hydroxyl value is less than 5, the polyol has a high viscosity and the workability deteriorates. If the hydroxyl value exceeds 30, the physical properties of the resulting polyurethane resin will deteriorate.

  The polyoxyalkylene polyol (A) may be a mixture of two or more polyols. In the case of a mixture, the average value of the hydroxyl value and the degree of unsaturation may be within the above ranges.

(Lactone polyol)
In the present invention, a lactone polyol is produced by reacting the polyoxyalkylene polyol (A) with a lactone.

  Examples of the lactone include ε-caprolactone, γ-valerolactone, and δ-valerolactone, and ε-caprolactone is particularly preferable. The amount of the lactone used is preferably such that the polyol (A) / lactone has a mass ratio of 20 to 98/2 to 80, and particularly preferably 55 to 98/2 to 45. Moreover, 4-28 are preferable and, as for the hydroxyl value of the reaction product obtained, 4-25 are especially preferable.

  When reacting, as a catalyst, organic titanium compounds such as tetrabutyl titanate and tetrapropyl titanate, tin 2-ethylhexanoate, dibutyltin dilaurate, dibutyltin oxide, stannous chloride, stannous bromide, first iodide A tin compound such as tin may be used at 0.05 to 1000 ppm. Moreover, as reaction temperature, 130-240 degreeC, Furthermore, 140-230 degreeC is preferable.

(Polyurethane resin)
In the present invention, a polyurethane resin can be produced by reacting a polyol containing the lactone-based polyol with a polyisocyanate compound. As a method for producing the polyurethane resin, known methods such as a one-shot method and a prepolymer method can be employed.

  In the present invention, a prepolymer method, that is, a method of producing a polyurethane resin by producing an isocyanate group-terminated prepolymer and further reacting with a curing agent (polyol, polyamine, etc.) is more preferred. In this case, a lactone polyol may be used as a raw material polyol for the isocyanate group-terminated prepolymer, and a lactone polyol may be used as a curing agent. The selection is preferably made according to the use and the required physical properties of the polyurethane resin, but the former is particularly preferable.

  Hereinafter, although the manufacturing method of the polyurethane resin by a prepolymer method is described in detail, this invention is not limited to this method. As the raw material polyol for the isocyanate group-terminated prepolymer, the lactone-based polyol may be used alone, or other polyols may be mixed and used. Moreover, when using the said lactone type polyol as a hardening | curing agent, you may use the polyol which does not contain the said lactone type polyol as a raw material polyol of an isocyanate group terminal prepolymer. From the viewpoint of physical properties, it is more preferable to use a lactone-based polyol as the raw material polyol of the isocyanate group-terminated prepolymer, and it is particularly preferable to use the lactone-based polyol alone.

  Examples of polyols other than the lactone-based polyol that can be used include polyoxyalkylene polyols and polyester polyols. The thing of a hydroxyl value of 5-100 is preferable, and the thing of 5-60 is more preferable. As the polyoxyalkylene polyol, polyoxytetramethylene polyol, polyoxyalkylene polyol (A), and other polyoxyalkylene polyols having a relatively high total unsaturation can be used.

  When using a lactone-type polyol and another polyol together, the use ratio is preferably a ratio of 10 to 90/90 to 10 and particularly preferably a ratio of 40 to 90/60 to 10 by mass ratio.

(Polyisocyanate compound)
Examples of the polyisocyanate compound that can be used in the present invention include aromatic polyisocyanates such as diphenylmethane diisocyanate, polyphenylene polymethylene polyisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and xylene diisocyanate, and hexamethylene diisocyanate. Aliphatic polyisocyanates such as aliphatic polyisocyanates, isophorone diisocyanates, 4,4′-methylenebis (cyclohexyl isocyanate), and these polyisocyanates are urethane-modified, burette-modified, allophanate-modified, carbodiimide-modified, isocyanurate-modified. Examples include the body. Aromatic diisocyanates are preferred and diphenylmethane diisocyanate is preferred in terms of reactivity and the viscosity of the resulting isocyanate group-terminated prepolymer.

(Prepolymer)
The isocyanate group-terminated prepolymer can be produced by reacting the polyol and the polyisocyanate compound at a ratio of isocyanate group / hydroxyl group (molar ratio) of 2 to 10, preferably 3 to 6. When the molar ratio is less than 2, the viscosity of the prepolymer increases and the workability decreases, whereas when the molar ratio exceeds 10, there is a problem that foaming tends to occur.

  The isocyanate group content (in terms of mass) of the prepolymer is preferably 0.1 to 10%, more preferably 0.3 to 6.0%, and most preferably 2 to 4%. When the isocyanate group content is less than 0.1%, the viscosity of the prepolymer increases and the workability decreases, and when the isocyanate group content exceeds 10%, foaming tends to occur.

  The isocyanate group-terminated prepolymer can be produced by an ordinary known method. For example, it can be produced by subjecting a polyisocyanate compound and the polyoxyalkylene polyol to a heat reaction at 60 to 100 ° C. for 1 to 20 hours in a dry nitrogen stream.

(Curing agent)
In the present invention, a polyurethane resin can be produced by reacting the prepolymer with a curing agent. As the curing agent, a high molecular weight polyol, a low molecular weight polyol, a polyamine, or the like can be selected in accordance with the physical properties of the polyurethane which is the final product.

  As the high molecular weight polyol, polyoxyalkylene polyol, polyester polyol, or the lactone-based polyol in the present invention can be used. As the polyoxyalkylene polyol, polyoxyalkylene polyols (A) and polyoxyalkylene polyols having a relatively high total unsaturation other than (A) can be used. The high molecular weight polyol preferably has a hydroxyl value of 5 to 112.

  As the low molecular weight polyol, a low molecular weight polyol having a molecular weight of 500 or less can be used. Low molecular weight polyols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2 -Dihydric alcohols such as methyl-1,5-heptanediol and cyclohexane-1,4-dimethanol.

  Examples of the polyamine include aliphatic amines and alicyclic amines such as an aromatic diamine compound in which an amino group is directly bonded to an aromatic ring and a diamine compound in which an amino group is bonded to an aromatic ring via an alkylene group.

  Specifically, diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene, 4,4′-diaminodiphenylmethane, 3,3′-dimethyl-4,4′-diaminodiphenylmethane, 3,3′- Fragrances such as diethyl-4,4′-diaminodiphenylmethane, 3,5-diethyl-2,4-diaminotoluene, 3,5-diethyl-2,6-diaminotoluene, m-xylylenediamine, p-xylylenediamine And aliphatic diamines such as aliphatic amines, ethylene diamine, propylene diamine and isophorone diamine, and alicyclic diamines such as piperazine and piperazine derivatives.

(reaction)
The ratio when the prepolymer and the curing agent are reacted is preferably such that the active hydrogen-containing group in the curing agent / isocyanate group in the prepolymer is 0.7 to 1.2, and 0.85 to 1.05. The ratio is preferably. The reaction temperature is preferably 0 to 30 ° C. If it is less than 0 ° C., the reaction is too slow and takes a long time. If the temperature exceeds 30 ° C., the reaction is too fast and the reaction occurs in a non-uniform state before being sufficiently mixed.

  You may contain the well-known urethanation reaction catalyst for making a prepolymer and a hardening | curing agent react. For example, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctoate, organotin compounds such as tin 2-ethylhexanoate, iron compounds such as iron acetylacetonate and ferric chloride; tertiary amines such as triethylamine and triethylenediamine Etc. Of these, organotin compounds are preferred.

  The addition amount of the catalyst is preferably 0.0001 to 0.1 parts by mass, particularly preferably 0.001 to 0.01 parts by mass with respect to 100 parts by mass in total of the prepolymer and the curing agent. If the amount is less than 0.0001 parts by mass, the time until the molded product can be removed becomes long. If the amount exceeds 0.1 parts by mass, the pot life after mixing the reaction components becomes too short.

  The reaction between the prepolymer and the curing agent can also be performed in a solvent. For example, a prepolymer can be produced in a solvent to obtain a prepolymer solution, and a curing agent can be added thereto to carry out the reaction in the solvent. As the solvent, a water-soluble polar solvent such as dimethylformamide, dimethylacetamide, dimethyl sulfoxide or the like is preferably used. Moreover, you may use together terminal group terminators, such as diethylamine, dibutylamine, and diethanolamine, as a molecular weight regulator of a polyurethane resin.

  In producing the polyurethane resin in the present invention, additives such as the following fillers, reinforcing agents, stabilizers, flame retardants, mold release agents, and antifungal agents can be blended. Fillers and reinforcing agents include carbon black, aluminum hydroxide, calcium carbonate, titanium oxide, silica, glass, bone meal, wood flour, and fiber flakes. Stabilizers include antioxidants, UV absorbers, and light stabilizers. As flame retardants, chloroalkyl phosphate, dimethylmethylphosphonate, ammonium polyphosphate, organic bromine compounds, etc. as mold release agents, waxes, soaps, silicone oils, etc., and as anti-mold agents, pentachloro Examples include phenol, pentachlorophenol laurate, and bis (tri-n-butyltin) oxide.

  The polyurethane resin of the present invention preferably contains no plasticizer. The polyurethane resin of the present invention has the effect of being excellent in workability and the effect of producing a low-hardness polyurethane resin without blending a plasticizer.

  In the present invention, by using a specific lactone-based polyol, it is possible to obtain a polyurethane resin that simultaneously satisfies low hardness, high strength, high elongation, and elastic recovery at low temperature.

  Accordingly, the polyurethane resin according to the present invention is used for applications requiring low hardness and high strength, for example, for office equipment such as resin molding mold materials, paper feed rollers, paper discharge rollers, transfer rollers, development rollers, and charging rollers. It is useful for various rollers, various blades used for screen printing, seal materials, vibration-proof materials, shock absorbers, and the like.

  Further, the polyurethane resin according to the present invention can produce a polyurethane resin having a high elongation and a high rebound resilience, and therefore is useful for applications such as synthetic leather and spandex. When used in spandex applications, conventional urethane resins using polyoxytetramethylene polyol had a problem of low elastic recovery at low temperatures (0 to 50 ° C), but this point was improved in the urethane resin of the present invention. it can.

  When the polyurethane resin according to the present invention is used as a synthetic leather, the reaction is carried out in a solvent to obtain a polyurethane resin solution, which is applied to a base fabric, and then the solvent is removed to obtain the synthetic leather. When used as spandex, an elastic yarn can be obtained from the polyurethane resin solution obtained by the reaction as described above by a dry spinning method or a wet spinning method.

  The contents of the present invention will be described below with reference to examples. The number of parts indicates the number of parts by mass.

(material)
As the polyol, polyoxypropylene polyol obtained by ring-opening polymerization of propylene oxide using the initiator and catalyst shown in Table 1 was used. Table 1 shows the hydroxyl value (unit: mgKOH / g) and the total unsaturation (unit: meq / g) of each polyol. In the table, DMC represents a zinc hexacyanocobaltate complex catalyst, and KOH represents a potassium hydroxide catalyst. Polyol c1 is a polyoxytetramethylene polyol having 2 hydroxyl groups and 56 hydroxyl values.

(Polyol synthesis)
(Examples 1-8)
The types and parts of polyol shown in Table 2 and the parts of ε-caprolactone shown in Table 2 as raw materials were charged into the reactor, and the temperature was raised to 140 ° C. while stirring in a nitrogen atmosphere. Further, 0.002 part of tetrabutoxytitanium was added, the temperature was raised to 170 ° C., and the mixture was reacted for 8 hours to obtain polyols (P1 to P5, Q1 to Q3). Table 2 shows the hydroxyl value (unit: mgKOH / g) of the obtained polyol.

(Application to low hardness urethane rubber)
(Examples 9 to 12)
The types and parts of polyols shown in Tables 3 to 4 and the types and parts of polyisocyanate compounds shown in Tables 3 to 4 were reacted in a nitrogen atmosphere at 80 ° C. for 7 hours to obtain isocyanate group-terminated prepolymers. Tables 3 to 4 show the isocyanate group content (NCO amount in the table) of the obtained prepolymer.

  Next, with respect to 100 parts of the obtained prepolymer, 0.05 parts of dibutyltin dilaurate (hereinafter referred to as DBTDL) as a curing agent and the types and parts of polyols shown in Tables 3 to 4 were added at 100 ° C. A polyurethane resin was obtained by reacting for 10 hours. Tables 3 to 4 show the physical properties of the obtained polyurethane resin. The physical properties were evaluated according to JIS K 6301.

  In the table, MDI represents 4,4'-diphenylmethane diisocyanate (trade name Millionate MT manufactured by Nippon Polyurethane Co., Ltd.), and TDI represents 2,4-tolylene diisocyanate (trade name Millionate T-100 manufactured by Nippon Polyurethane Co., Ltd.). Examples 9 to 10 and 12 to 13 are examples, and examples 11 and 14 to 16 are comparative examples.

  In Examples 9 to 10, as compared with Example 11, a resin having lower hardness, higher strength and higher elongation was obtained. In Examples 12 to 13, resins having low hardness and high strength and high rebound resilience were obtained. In Examples 14 to 16, all of low hardness, high strength, and high rebound resilience were satisfied. The resin could not be obtained.

(Application to thermoplastic polyurethane resin)
(Examples 17 to 19)
The types and parts of polyols shown in Table 5 and the types and parts of polyisocyanate compounds shown in Table 5 were reacted at 80 ° C. for 7 hours in a nitrogen atmosphere to obtain isocyanate group-terminated prepolymers. Table 5 shows the isocyanate group content (NCO amount in the table) of the obtained prepolymer.

  Next, 100 parts of the obtained prepolymer was added with 1,4-butanediol in the number of parts shown in Table 5 as a curing agent and 0.05 part of dibutyltin dilaurate as a catalyst, and reacted at 120 ° C. for 10 hours. Thus, a polyurethane resin was obtained.

  The obtained resin composition is crushed into flakes by a pulverizer, and then the flaky resin composition is extruded into a film having a thickness of 100 μm using an extruder with a die temperature of 125 ° C. A resin composition was obtained. In addition, Example 17 is an Example and Examples 18-19 are comparative examples.

  In Example 18, the resin was thermally decomposed and foamed in the discharge part of the extrusion molding machine, and a film-like resin composition could not be obtained.

(Application to polyurethane urea resin by solution polymerization)
(Examples 20 to 23)
The types and parts of polyols shown in Table 6 and the types and parts of polyisocyanate compounds shown in Table 6 were reacted at 80 ° C. for a time in a nitrogen atmosphere to obtain isocyanate group-terminated prepolymers. Table 6 shows the isocyanate group content (NCO amount in the table) of the obtained prepolymer.

  The obtained prepolymer was dissolved in N, N′-dimethylacetamide (DMAC) to obtain a urethane prepolymer solution having a solid content of 30% by mass. Then, a solution obtained by dissolving the parts of m-xylylenediamine shown in Table 6 and the parts of diethylamine shown in Table 6 in DMAC so as to have a concentration of 30% by weight was used as a curing agent, and the mixture was vigorously stirred at room temperature. In addition to 100 parts of the urethane prepolymer solution, a polymerization reaction was performed to obtain a polyurethane urea resin solution.

  The polyurethane urea resin solution was evaporated by evaporating DMAC, and further subjected to heat treatment at 140 ° C. for 30 minutes to prepare a film sample having a thickness of about 100 μm. The sample was cured at room temperature for 10 days and then measured for physical properties as described below. The results are shown in Table 6. Examples 20 to 21 are examples, and examples 22 to 23 are comparative examples.

Claims (2)

  In a method for producing a polyurethane resin by reacting a polyol and a polyisocyanate compound, as at least a part of the polyol, (1) a hydroxyl value of 5 to 30 and (2) a polyoxyalkylene having a total degree of unsaturation of 0.07 or less A method for producing a polyurethane resin, comprising using a lactone-based polyol obtained by reacting a polyol (A) with a lactone.   In a method for producing a polyurethane resin by reacting an isocyanate group-terminated prepolymer obtained by reacting a polyol with a polyisocyanate compound and a curing agent, (1) a hydroxyl value of 5 to 30 and ( 2) A method for producing a polyurethane resin, comprising using a lactone-based polyol obtained by reacting a polyoxyalkylene polyol (A) having a total unsaturation of 0.07 or less and a lactone.