Method for predicting physical properties and method for preparing polyurethane resin composition

Abstract

To provide a method for predicting physical properties, which is capable of predicting the physical properties of a polyurethane resin composition from its raw materials.SOLUTION: The present invention provides a method for predicting physical properties, which is capable of predicting the physical properties of a polyurethane resin composition from the theoretical level of crystallinity of the diol constituting the polyurethane resin contained in the polyurethane resin composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to methods for predicting physical properties and preparing polyurethane resin compositions. [Background technology]

[0002] Polyurethane resin compositions containing polyurethane resins are used for various purposes, for example, as reactive hot melt adhesives whose main component is a urethane prepolymer. After bonding, reactive hot melt adhesives develop a certain degree of adhesive strength in a short time due to the cooling and solidification of the adhesive itself. Thereafter, the isocyanate groups of the urethane prepolymer react with moisture in the air or on the surface of the adherend to increase the molecular weight, and crosslinking occurs to form an adhesive layer, thereby developing heat resistance. Therefore, reactive hot melt adhesives whose main component is a urethane prepolymer exhibit good adhesive strength even at high temperatures.

[0003] Reactive hot melt adhesives containing urethane prepolymers may exhibit a high modulus of elasticity after curing. If the modulus of elasticity of the adhesive after curing is excessively high, the impact resistance of the bonded portion tends to decrease. Therefore, for example, Patent Document 1 proposes a reactive hot melt adhesive that contains a urethane prepolymer and a curing catalyst and can reduce the modulus of elasticity after curing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-33405 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to obtain a polyurethane resin composition having a desired elastic modulus, such as the reactive hot melt adhesive described in Patent Document 1, it was necessary to repeat the process of compounding the polyurethane resin composition with reference to past experience and measuring the elastic modulus after curing several times until the desired elastic modulus was obtained. In addition, a similar process was required when obtaining a polyurethane resin composition having a desired physical property other than the elastic modulus. If there was a method for estimating the physical properties of the polyurethane resin composition without measuring the physical properties of the polyurethane resin composition at the stage of determining the compounding of the polyurethane resin composition, it would be possible to reduce the number of procedures, considerations, etc. required to obtain a desired polyurethane resin composition.

[0006] The present disclosure has been made in consideration of the above, and aims to provide a method for predicting physical properties that enables prediction of the physical properties of a polyurethane resin composition from raw materials of the polyurethane resin composition, and a method for preparing a polyurethane resin composition using this prediction method. [Means for solving the problem]

[0007] Specific means for solving the above problems include the following aspects. <1> A method for predicting physical properties of a polyurethane resin composition from a theoretical amount of crystallinity of a diol constituting a polyurethane resin contained in the polyurethane resin composition. <2> The polyurethane resin includes a urethane prepolymer having a polyurethane chain including a diol-derived structural unit and a diisocyanate-derived structural unit, and an isocyanate group bonded to an end of the polyurethane chain. <1> The method for predicting physical properties described in <3> The diol includes a polyester diol. <1> or <2> The method for predicting physical properties described in <4> The diol includes a crystalline diol and an amorphous diol. <1> ~ <3> 13. A method for predicting physical properties according to any one of the preceding claims. <5> The melting point of the crystalline diol is greater than 15° C. <4> The method for predicting physical properties described in <6> The physical properties of the polyurethane resin composition that are estimated are the crystallinity of the cured product, the elastic modulus of the cured product, the foaming property, the initial adhesive strength, or the open time. <1> ~ <5> A method for predicting physical properties described in any one of the above. <7> The polyurethane resin composition is a reactive hot melt adhesive. <1> ~ <6> 13. A method for predicting physical properties according to any one of the preceding claims. <8> <1> ~ <7> 2. A method for preparing a polyurethane resin composition, comprising: preparing a polyurethane resin composition containing a polyurethane resin based on physical properties of the polyurethane resin composition predicted by the method for predicting physical properties described in any one of 1 to 11. Effect of the Invention

[0008] According to the present disclosure, there is provided a method for predicting physical properties of a polyurethane resin composition from its raw materials, and a method for preparing a polyurethane resin composition using this prediction method. [Brief description of the drawings]

[0009] [Figure 1] 1 is a graph showing the results of a regression analysis using the theoretical amount of crystallinity of a diol and the crystallinity of a reactive hot melt adhesive. [Diagram 2] 1 is a graph showing the results of a regression analysis using the theoretical amount of crystallinity of a diol and the tensile modulus of a reactive hot melt adhesive. [Diagram 3] 1 is a graph showing the results of a regression analysis using the crystallinity and tensile modulus results of reactive hot melt adhesives. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In the present disclosure, the term "step" includes not only a step that is independent of other steps, but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved. In the present disclosure, a numerical range indicated using "~" includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple types of the corresponding substance. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified.

[0011] Hereinafter, the embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless otherwise specified. The same applies to the numerical values ​​and their ranges, and do not limit the present disclosure.

[0012] <Method of predicting physical properties> The method of predicting physical properties according to the present disclosure is a method of predicting physical properties of a polyurethane resin composition from the theoretical amount of crystallinity of a diol constituting a polyurethane resin contained in the polyurethane resin composition.

[0013] A polyurethane resin composition and a resin material such as a cured product obtained therefrom are a mixture of a crystalline portion in which polymer chains are regularly arranged and an amorphous portion in which polymer chains are randomly arranged. The present inventors have focused on the fact that the mechanical strength, density, thermal properties, and other physical properties of a resin material having a crystalline portion and an amorphous portion are greatly affected by the crystallinity, and have focused on the crystallinity of the polyurethane resin composition and the crystallinity of the diol component constituting the polyurethane resin contained in the polyurethane resin composition. Then, by analyzing the relationship between the crystallinity of the polyurethane resin composition, the crystallinity of the diol component, and the physical properties of the polyurethane resin composition, a method for estimating the physical properties of the polyurethane resin composition from the theoretical amount of the crystallinity of the diol has been found.

[0014] In the method of predicting physical properties disclosed herein, it is possible to predict the physical properties of a polyurethane resin composition prepared using a diol from the theoretical amount of crystallinity, which is a physical property value of the diol constituting the polyurethane resin (i.e., the physical properties of the raw material). This makes it possible to predict the physical properties of the polyurethane resin composition without measuring them at the stage of determining the blend of the polyurethane resin composition, thereby reducing the number of procedures, considerations, etc. required to obtain a desired polyurethane resin composition.

[0015] In the method of estimating physical properties of the present disclosure, a correlation equation may be calculated in advance by regression analysis using the theoretical amount of crystallinity as an explanatory variable and the physical properties of the polyurethane resin composition as objective variables. For example, the theoretical amount of crystallinity is plotted on the horizontal axis, the physical properties of the polyurethane resin composition are plotted on the vertical axis, and multiple data on the theoretical value of crystallinity and the physical properties of the polyurethane resin composition are plotted on a graph. Then, a correlation equation expressed by y=ax+b is obtained by approximating with a linear function using the least squares method. Thereby, by substituting the theoretical amount of crystallinity of the diol constituting the polyurethane resin into the correlation equation calculated in advance, a value corresponding to the physical properties of the polyurethane resin composition can be calculated, and the physical properties of the polyurethane resin composition can be estimated.

[0016] In the present disclosure, the theoretical amount of crystallinity of the diol constituting the polyurethane resin can be calculated as follows. When the polyurethane resin contains only one type of diol, the theoretical crystallinity corresponds to the crystallinity of the one type of diol. When the polyurethane resin contains two or more diols, the degree of crystallinity of each diol is determined, and the proportion (mass%) of each diol relative to all components constituting the polyurethane resin (for example, the total of the diol component, diisocyanate component, and other components contained as necessary) is determined, and the theoretical amount Ct of the degree of crystallinity of the diol can be calculated based on the following formula (2).

[0017]

number

[0018] In formula (2), Cx represents the crystallinity (%) of the specific diol, mx represents the content (mass%) of the specific diol relative to all components constituting the polyurethane resin, and m1+m2+···+mn=100.

[0019] The crystallinity of each diol may be determined by a value provided by the manufacturer of the diol, or may be determined by measuring the crystallinity using an X-ray diffraction apparatus. When measuring the crystallinity of each diol using an X-ray diffractometer, each diol is melted at a temperature above its melting point, and a film with a thickness of about 100 μm is prepared using a low-pressure press at 100°C. The prepared film is subjected to XRD measurement using an X-ray diffractometer (e.g., PANalytical's Empyrean X-ray diffractometer) to obtain a spectrum. The spectrum is subjected to waveform separation, and the crystallinity of the diol is calculated using the following formula. Crystallinity of diol (%) = [(sum of crystalline peak areas) / (sum of crystalline peak areas + sum of amorphous peak areas)] × 100 For diols that do not have a melting point, the degree of crystallinity is considered to be 0%.

[0020] The physical properties of the polyurethane resin composition to be estimated are not particularly limited, and examples thereof include the crystallinity of the cured product, the elastic modulus of the cured product (e.g., tensile modulus, flexural modulus, and compressive modulus), foamability (e.g., foaming rate), initial adhesive strength, and open time. The initial adhesive strength means, for example, the adhesive strength at room temperature after 5 minutes have elapsed after applying the polyurethane resin composition to a substrate at 120°C. The open time means the time from immediately after application of the polyurethane resin composition to a substrate or the like (for example, after application at room temperature) until the stickiness disappears.

[0021] The polyurethane resin preferably contains a urethane prepolymer having a polyurethane chain including a constituent unit derived from a diol and a constituent unit derived from a diisocyanate, and an isocyanate group bonded to an end of the polyurethane chain.

[0022] The polyurethane chain constituting the urethane prepolymer is usually a polymer chain formed by a polymerization reaction between a diol and a diisocyanate. The polyurethane chain may contain other bonds such as urea bonds in addition to urethane bonds. The isocyanate group bonded to the end of the polyurethane chain is usually derived from a diisocyanate. The polyurethane chain may further contain a structural unit derived from a polyol having three or more hydroxyl groups and / or a structural unit derived from a polyisocyanate having three or more isocyanate groups. In this case, the total ratio of the structural unit derived from a polyol having three or more hydroxyl groups and the structural unit derived from a polyisocyanate having three or more isocyanate groups is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and particularly preferably 1% by mass or less, based on the total amount of the structural units constituting the polyurethane chain.

[0023] The diol may be composed of one kind of diol, or may be composed of two or more kinds of diols, for example, two or more kinds of diols having different crystallinity.

[0024] The diol includes a crystalline diol and an amorphous diol. The diol contains at least one of a crystalline diol and an amorphous diol, and preferably contains a crystalline diol and an amorphous diol.

[0025] In the present disclosure, a "crystalline diol" refers to a diol that forms crystals at 15° C. The formation of crystals at 15° C. is confirmed, for example, by the observation of a melting point at a temperature higher than 15° C. by differential scanning calorimetry. In the present disclosure, the term "amorphous diol" refers to a diol that is not classified as a crystalline diol, and may be, for example, a diol that does not have a melting point observed by differential scanning calorimetry or that has a melting point observed at 15°C or lower.

[0026] The melting point of the crystalline diol is preferably 15° C. or higher. The upper limit of the melting point of the crystalline diol is not particularly limited.

[0027] Examples of diols include polyester diols, polyether diols, polyether ester polyols, polyurethane polyols, polycarbonate polyols, and polyolefin polyols. Each of these may be independently crystalline or amorphous. Among them, the diol is preferably a polyester diol or a polyether diol. These may be used alone or in combination of two or more. Also, one or more crystalline diols and one or more amorphous diols may be used in combination.

[0028] The crystalline diol may include a crystalline polyester diol. The amorphous diol may include at least one of an amorphous polyester diol and an amorphous polyether diol.

[0029] The polyester diol is preferably a compound represented by the following formula (1). The polyester diol is, for example, a polycondensation product of a diol compound represented by the following formula (11) and a dicarboxylic acid compound represented by the following formula (12).

[0030] [ka]

[0031] [ka]

[0032] In formulas (1), (11) and (12), R 1 and R 2 Each of R independently represents a linear or branched aliphatic group, an alicyclic group, or an aromatic group. 1 and R 2 may be the same or different. n is an integer. R 1R may be a linear or branched aliphatic group having 2 to 15 carbon atoms. 2 may be a linear or branched aliphatic group having 2 to 15 carbon atoms and / or an aromatic group.

[0033] Examples of the diol compound represented by formula (11) include aliphatic or alicyclic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, pentanediol, hexanediol, 2,2-dimethyl-1,3-propanediol, 2-methylpropanediol, 2,4,4-trimethyl-1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol; and aromatic diols such as 4,4'-dihydroxydiphenylpropane, bisphenol A, bisphenol F, pyrocatechol, resorcinol, and hydroquinone. These diol compounds may be used alone or in combination of two or more.

[0034] Examples of the dicarboxylic acid compound represented by formula (12) include aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid; and aliphatic or alicyclic polycarboxylic acids such as maleic acid, fumaric acid, aconitic acid, 1,2,3-propanetricarboxylic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, cyclohexane-1,2-dicarboxylic acid, and 1,4-cyclohexanediene-1,2-dicarboxylic acid. The dicarboxylic acid compound may be used alone or in combination of two or more. Instead of the dicarboxylic acid compound, a corresponding anhydride or carboxylic acid alkyl ester may be used.

[0035] The polyester diol represented by formula (1) is, for example, R 2 When R is a 1,4-butanediyl group, a 1,6-hexanediyl group, or a 1,8-octanediyl group, the polyester diol tends to be crystalline. Examples of crystalline polyester diols include polycondensates of 1,6-hexanediol and adipic acid (R 1is a 1,6-hexanediyl group, and R 2 polycondensation product in which R is a 1,4-butanediyl group), polycondensation product of 1,6-hexanediol and sebacic acid (R 1 is a 1,6-hexanediyl group, and R 2 is a 1,8-octanediyl group), a polycondensate of 1,6-hexanediol and suberic acid (R 1 and R 2 is a 1,6-hexanediyl group), and a polycondensation product of 1,4-butanediol and adipic acid (R 1 and R 2 (polycondensation products in which the alkyl group is a 1,4-butanediyl group).

[0036] The number average molecular weight (Mn) of the crystalline polyester diol may be 500 to 10,000, 800 to 9,000, or 1,000 to 8,000, from the viewpoints of waterproofness and final adhesive strength.

[0037] In the present disclosure, the number average molecular weight (Mn) is a value measured by gel permeation chromatography (GPC) and converted into a standard polystyrene equivalent. The GPC measurement can be performed under the following conditions. Columns: "Gelpack GLA130-S", "Gelpack GLA150-S" and "Gelpack GLA160-S" (Resonac Corporation, HPLC packed columns) Eluent: Tetrahydrofuran Flow rate: 1.0mL / min Column temperature: 40℃ Detector: RI

[0038] The polyether diol may have a primary hydroxyl group (-CH2OH), or may have a primary hydroxyl group and a secondary hydroxyl group. Examples of polyether diols having a primary hydroxyl group include polyethylene glycol and polytetramethylene ether glycol. Examples of polyether diols having a secondary hydroxyl group include polypropylene glycol. These may be used alone or in combination of two or more. The amorphous polyether diol may be polypropylene glycol. This polyether diol is usually amorphous.

[0039] The polyether diol may be, for example, a polymer of an oxirane such as ethylene oxide, propylene oxide, or tetrahydrofuran. When propylene oxide, in which the α-carbon of the ether bond is a secondary carbon atom, is used as the oxysilane, β-cleavage of the propylene oxide usually proceeds, and polypropylene glycol having a secondary hydroxyl group tends to be obtained, but by predominantly α-cleaving the propylene oxide, polypropylene glycol having a primary hydroxyl group can be obtained at a high rate. An example of a commercially available polypropylene glycol containing a high rate of primary hydroxyl groups is "FF-2100" (manufactured by Sanyo Chemical Industries, Ltd.).

[0040] The number average molecular weight (Mn) of the polyether diol having a primary hydroxyl group may be 500 to 20,000, 700 to 15,000, or 1,000 to 10,000, from the viewpoint of obtaining an appropriate lamination time and initial adhesiveness after application.

[0041] The urethane prepolymer contains a polyurethane chain including a diol-derived structural unit and a diisocyanate-derived structural unit. The diol-derived structural unit preferably includes a crystalline diol-derived structural unit and an amorphous diol-derived structural unit. The diol-derived structural unit may include a crystalline polyester diol-derived structural unit, an amorphous polyester diol-derived structural unit, and an amorphous polyether diol-derived structural unit.

[0042] When the urethane prepolymer contains a constituent unit derived from a crystalline polyester diol, the content of the constituent unit derived from the crystalline polyester diol may be 5% by mass to 100% by mass, 10% by mass to 75% by mass, or 15% by mass to 70% by mass, relative to the total mass of the constituent units derived from the diol and polyol (having three or more hydroxyl groups) constituting the urethane prepolymer.

[0043] When the urethane prepolymer contains a structural unit derived from an amorphous polyester diol, the content of the structural unit derived from the amorphous polyester diol may be 10% by mass to 95% by mass, 20% by mass to 90% by mass, or 25% by mass to 85% by mass, relative to the total mass of the structural units derived from the diol and polyol (having three or more hydroxyl groups) constituting the urethane prepolymer.

[0044] When the urethane prepolymer contains a structural unit derived from a polyether diol (which may hereinafter be read as an amorphous polyether diol), the content of the structural unit derived from the polyether diol may be more than 0 mass% and 30 mass%, may be 1 mass% to 25 mass%, or may be 3 mass% to 20 mass%, relative to the total mass of the structural units derived from the diol and polyol (having three or more hydroxyl groups) constituting the urethane prepolymer.

[0045] Diisocyanate is a compound having two isocyanate groups. The diisocyanate may be, for example, an aromatic diisocyanate, an aliphatic diisocyanate, an alicyclic diisocyanate, or a combination of two or more selected from these.

[0046] Examples of aromatic diisocyanates include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 2,4'- or 4,4'-diphenylmethane diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, m- or p-isocyanatophenylsulfonyl isocyanate, m- or p-xylylene diisocyanate, and α,α,α',α'-tetramethylxylylene diisocyanate.

[0047] Examples of the aliphatic diisocyanate include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl) fumarate, bis(2-isocyanatoethyl) carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate.

[0048] Examples of the alicyclic diisocyanate include isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexene-1,2-dicarboxylate, and 2,5- or 2,6-norbornane diisocyanate.

[0049] The diisocyanate may be 2,4'- or 4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 2,4- or 2,6-tolylene diisocyanate, hexamethylene diisocyanate, m- or p-xylylene diisocyanate, p-phenylene diisocyanate, isophorone diisocyanate, or a combination of two or more selected from these.

[0050] The urethane prepolymer having an isocyanate group at the end can be synthesized, for example, by making the equivalent of the isocyanate group to the hydroxyl group in the polymerization reaction excessive. For example, the ratio of isocyanate group equivalent / hydroxyl group equivalent ((NCO) equivalent / (OH) equivalent) may be 1.3 or more, or 1.5 to 3.5. The isocyanate group equivalent here includes the amount of isocyanate groups contained in a polyisocyanate having three or more isocyanate groups when used. The hydroxyl group equivalent includes the amount of hydroxyl groups contained in a polyol having three or more hydroxyl groups when used. When the ratio of isocyanate group equivalent / hydroxyl group equivalent is within these ranges, the increase in viscosity of the urethane prepolymer can be suppressed, and the workability tends to be easily improved. In addition, foaming is less likely to occur during the moisture curing reaction of the reactive hot melt adhesive, and the decrease in adhesiveness tends to be easily suppressed.

[0051] The use of the polyurethane resin composition is not particularly limited. For example, the polyurethane resin composition may be used as an adhesive, a paint, a heat insulating material, a sound absorbing material, a component of an industrial product such as an automobile, etc. The polyurethane resin composition may be a reactive hot melt adhesive.

[0052] The polyurethane resin composition may contain components other than the polyurethane resin, such as resin components other than the polyurethane resin, curing catalysts, pigments, dyes, antioxidants, ultraviolet absorbers, surfactants, flame retardants, and fillers.

[0053] <Method for preparing polyurethane resin composition> The method for preparing a polyurethane resin composition according to the present disclosure includes preparing a polyurethane resin composition containing a polyurethane resin based on the physical properties of the polyurethane resin composition predicted by the method for predicting physical properties according to the present disclosure.

[0054] For example, by using the method of estimating physical properties of the present disclosure, it is possible to estimate the physical properties of a polyurethane resin composition prepared using a diol from the theoretical amount of crystallinity, which is a physical property value of the diol constituting the polyurethane resin (i.e., the physical properties of the raw material). Therefore, for example, the theoretical amount of crystallinity of a diol in a specific combination in which the composition, type, etc. of the diol are adjusted is calculated, and if the physical properties of the polyurethane resin composition estimated from the theoretical value satisfy the desired conditions, a polyurethane resin composition containing a polyurethane resin may be prepared using the diol in the specific combination.

[0055] For example, the theoretical amount of crystallinity of the diol in a specific combination may be calculated, and it may be judged whether any of the physical properties of the polyurethane resin composition estimated from the theoretical value, such as the crystallinity of the cured product, the elastic modulus of the cured product (e.g., tensile modulus, flexural modulus, and compressive modulus), foamability (e.g., foaming rate), initial adhesive strength, or open time, exceeds a specific threshold value or is below a specific threshold value. Then, when it is judged that the specific threshold value is exceeded or is below a specific threshold value, the diol in the specific combination may be reacted with a polyisocyanate such as a diisocyanate to prepare a polyurethane resin composition containing a polyurethane resin. This makes it easier to prepare a polyurethane resin composition having desired physical properties while reducing the procedures and considerations required for the preparation of a polyurethane resin composition. In addition, even if a polyurethane resin composition having strictly desired physical properties cannot be obtained by the preparation method of the present disclosure, the desired polyurethane resin composition can be easily obtained by finely adjusting the composition of the diol, and the effort required to obtain the desired polyurethane resin composition can be reduced. EXAMPLES

[0056] The above embodiment will be specifically described below using examples, but the scope of the above embodiment is not limited to these examples.

[0057] [Example 1] <Preparation of reactive hot melt adhesive> A crystalline diol and an amorphous diol were prepared as the diol, and diphenylmethane diisocyanate (polyisocyanate (b) in the table) was prepared as the diisocyanate. A reactive hot melt adhesive, which is a polyurethane resin composition, was prepared as described below. Specifically, the following polyester polyols (a1)-1 to (a1)-3 were used as the crystalline diol, and the following polyester polyol (a2) was used as the amorphous diol. Polyester polyol (a1)-1: A crystalline polyester polyol whose main components are sebacic acid and 1,6-hexanediol (number of hydroxyl groups: 2, number average molecular weight: approximately 5000) Polyester polyol (a1)-2: A crystalline polyester polyol (hydroxyl group number: 2, number average molecular weight: approximately 5000) whose main components are adipic acid and 1,6-hexanediol. Polyester polyol (a1)-3: A crystalline polyester polyol whose main components are adipic acid and 1,4-butanediol (number of hydroxyl groups: 2, number average molecular weight: approximately 3000) Polyester polyol (a2): A non-crystalline polyester polyol whose main components are adipic acid, 1,4-butanediol, and neopentyl glycol (number of hydroxyl groups: 2, number average molecular weight: approximately 5000)

[0058] (Examples 1 to 6) The polyester polyol (diol) and polyisocyanate were used in the types and parts by mass shown in Table 1. The polyester polyol had been dehydrated in advance using a vacuum dryer, and the polyisocyanate was added to a reaction vessel so that the equivalent ratio ((NCO) equivalent / (OH) equivalent) of the isocyanate group of the polyisocyanate to the hydroxyl group of the polyester polyol was the value shown in Table 1, and mixed at 110°C for 1 hour until uniform. Next, the mixture was stirred under reduced pressure and degassed at 110°C for another 1 hour to obtain a reactive hot melt adhesive.

[0059] <Measurement of tensile modulus> The reactive hot melt adhesive was melted at 100°C to form a film with a thickness of 100 μm, and then left to stand in a thermo-hygrostat at a temperature of 23°C and a humidity of 50% for two days. The film was punched out with a No. 1 dumbbell to prepare a test piece, and the tensile modulus (MPa) of the test piece was measured using an autograph AGS-X (manufactured by Shimadzu Corporation) in accordance with JIS K-6251:2017. The results are shown in Table 1.

[0060] <Measurement of crystallinity> The reactive hot melt adhesive was melted at a temperature above the melting point, and a film with a thickness of about 100 μm was produced using a low-pressure press at 100 ° C. The produced film was subjected to XRD measurement using an X-ray diffraction device (product name: Empyrean; manufactured by PANalytical) to obtain a spectrum. The spectrum was subjected to waveform separation, and the crystallinity of the reactive hot melt adhesive was calculated using the following formula. Crystallinity (%) of reactive hot melt adhesive = [(sum of crystalline peak areas) / (sum of crystalline peak areas + sum of amorphous peak areas)] x 100

[0061] <Calculation of the theoretical amount of crystallinity of diol> The theoretical crystallinity (Ct) of the diol used in Example 1 was calculated based on the following formula (2). In formula (2), Cx represents the crystallinity (%) of a specific diol, and mx represents the content (mass%) of the specific diol relative to all components constituting the polyurethane resin. In addition, m1+m2+···+mn=100. The crystallinity of each diol was measured by XRD using the method described above. The results are shown in Table 1.

[0062]

number

[0063] <Measurement of tack-free time> The reactive hot melt adhesive was heated to 100°C to melt it, applied to a width of 1 mm, and the tack-free time, which is the time (unit: seconds) required for the adhesive to no longer adhere to the fingertip, was measured. The results are shown in Table 1.

[0064] <Measurement of initial adhesive strength> The initial adhesive strength was measured by preparing a reactive adhesive layer coating of 80 mm length x 25 mm width x 100 μm thickness on a polycarbonate film under an environment of 25°C temperature and 50% humidity, press-bonding it to a polycarbonate film of 100 mm length x 25 mm width x 100 μm thickness, and then performing a T-type peel strength test (peel speed: 100 mm / min) using a tensile tester (Shimadzu Corporation, EZ-Test EZ-SX) after 5 minutes to measure the adhesive strength. The results are shown in Table 1.

[0065] [Table 1]

[0066] A regression analysis was performed using the theoretical amount of crystallinity of the diol and the results of the crystallinity of the reactive hot melt adhesive. As shown in Figure 1, the coefficient of determination R 2 is 0.9112, confirming that there is a high correlation between the two. A regression analysis was performed using the theoretical amount of crystallinity of the diol and the results of the tensile modulus of the reactive hot melt adhesive. As shown in Figure 2, the coefficient of determination R 2 is 0.9946, confirming that there is a high correlation between the two. In addition, a regression analysis was performed using the results of the crystallinity and tensile modulus of the reactive hot melt adhesive. As shown in Figure 3, the coefficient of determination R 2 is 0.9578, confirming that there is a high correlation between the two. From the above results, it was confirmed that there is a high correlation between the theoretical crystallinity of the diol and the crystallinity or tensile modulus of the reactive hot melt adhesive, and that the physical properties of the reactive hot melt adhesive can be predicted from the theoretical crystallinity of the diol.

Claims

1. A method for predicting physical properties of a polyurethane resin composition from a theoretical amount of crystallinity of a diol constituting a polyurethane resin contained in the polyurethane resin composition.

2. The method for predicting physical properties according to claim 1 , wherein the polyurethane resin comprises a urethane prepolymer having a polyurethane chain including a structural unit derived from a diol and a structural unit derived from a diisocyanate, and an isocyanate group bonded to an end of the polyurethane chain.

3. The method for predicting physical properties according to claim 1 , wherein the diol includes a polyester diol.

4. The method for predicting physical properties according to claim 1 , wherein the diol includes a crystalline diol and an amorphous diol.

5. The method for predicting physical properties according to claim 4, wherein the melting point of the crystalline diol is greater than 15°C.

6. The method for predicting a physical property according to claim 1 , wherein the physical property of the polyurethane resin composition to be predicted is a crystallinity of the cured product, an elastic modulus of the cured product, foamability, initial adhesive strength or open time.

7. The method for predicting physical properties according to claim 1 , wherein the polyurethane resin composition is a reactive hot melt adhesive.

8. A method for preparing a polyurethane resin composition, comprising preparing a polyurethane resin composition containing a polyurethane resin based on physical properties of the polyurethane resin composition predicted by the method for predicting physical properties according to any one of claims 1 to 7.

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