JP7174478B2 - Low outgassing urethane hot melt adhesive composition - Google Patents

Description

The present invention relates to a novel hot-melt adhesive composition with low outgassing.

Conventionally, the upholstery covering the surface of a vehicle seat cushion is produced by attaching the upholstery layer to the surface of a laminated sheet in which a backing base fabric layer is formed on the back side of a cushioning layer made of foam, and then sewing the upholstery. ing. The back base fabric layer is provided to improve the slipperiness to improve the work of sewing and the work of attaching to the seat cushion after sewing, and to protect the back surface of the cushioning layer.

Here, for vehicle seat cushions, there are many polar materials such as urethane and nylon, and heat resistance is required, so reactive urethane hot-melt is generally applied. A vehicle seat using such a reactive urethane hot-melt is disclosed, for example, in Patent Document 1.

However, adhesives used for vehicle seat cushions are desired to contain less organic volatile matter that affects the human body.

As such a low outgassing hot melt adhesive, Patent Document 2 discloses a low outgassing olefinic hot melt adhesive.

JP 2017-136735 JP 2017-31273

However, although olefinic hot melt adhesives can achieve low VOC, their applications are limited from the viewpoint of heat resistance and the like, and it has been difficult to use them for vehicles.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a hot-melt adhesive composition having both good moist heat resistance and low outgassing properties. A second object of the present invention is to provide a hot-melt adhesive composition that exhibits sufficient initial adhesiveness even when used to adhere foams and the like.

As a result of extensive research, the inventors of the present invention have found that the above problems can be solved by using a specific adhesive composition, and completed the present invention. That is, the present invention is as follows.

The present invention (1) is
A urethane hot-melt adhesive composition containing a urethane prepolymer made from a polyol component (A) and a polyisocyanate (B),
The polyol component (A) comprises a crystalline polyester polyol (a-1) obtained by a condensation reaction of an aliphatic dicarboxylic acid having 10 to 12 carbon atoms and an aliphatic diol having 4 to 6 carbon atoms, and a polyether polyol (a- 2) containing
A low outgassing urethane hot melt adhesive composition, wherein the content of the polyether polyol (a-2) in the polyol component (A) is 30 to 80 parts by mass with respect to 100 parts by mass of the polyol component (A). It is a thing.
The present invention (2) is
The crystalline polyester polyol (a-1) is the low outgassing urethane hot-melt adhesive composition of the invention (1), having a number average molecular weight within the range of 1,000 to 5,000.
The present invention (3) is
The polyether polyol (a-2) is the low outgassing urethane hot melt adhesive composition of the invention (1) or (2), wherein the number average molecular weight is within the range of 1000 to 4000.
The present invention (4) is
The above inventions (1) to ( 3) The low outgassing urethane hot-melt adhesive composition.
The present invention (5) is
The total content of the amorphous polyester polyol, the polycarbonate diol and the low-molecular weight diol having a number average molecular weight of 500 or less in the polyol component (A) is 30 parts by mass or less per 100 parts by mass of the polyol component (A). There is a low outgassing urethane hot-melt adhesive composition according to the invention (4).
The present invention (6) is
The low outgassing urethane hot-melt adhesive composition according to any one of inventions (1) to (5), wherein the amount of organic volatile matter generated when heated at 90° C. is 150 ppm or less in terms of toluene.
The present invention (7) is
The low outgassing urethane hot-melt adhesive composition according to any one of the inventions (1) to (6), which is for vehicle members comprising foams, natural leathers, synthetic leathers, films, woven fabrics and non-woven fabrics.

ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the hot-melt-adhesive composition which has favorable heat-and-moisture resistance and low outgassing property.

Next, the hot-melt adhesive composition of the present invention will be specifically described in the following order, but the present invention is not limited thereto.
1 Component 2 Production method 3 Physical properties 4 Application 5 Application method

≪Ingredients≫
The hot melt adhesive composition according to the present invention is a low outgassing reactive urethane hot melt. The hot-melt adhesive composition according to the invention comprises an isocyanate-terminated polyurethane prepolymer as a base resin. Furthermore, other components may be included in the adhesive composition as required. When such a hot-melt adhesive composition is used, adhesion is exhibited by cooling and solidifying the polyurethane prepolymer in a molten state, and uncured isocyanate terminals react with moisture in the air to form a crosslinked structure. By forming, stronger adhesiveness is exhibited. Hereinafter, such a hot-melt adhesive composition may be referred to as a moisture-curable hot-melt adhesive composition, a reactive hot-melt adhesive composition, or the like.

・Base resin (polyurethane prepolymer)
Polyurethane prepolymer is produced by using polyol component (A) and polyisocyanate (B) as raw materials, and reacting polyisocyanate (B) in a stoichiometrically excessive amount with polyol component (A) to obtain polyurethane prepolymer. can get.

The polyol component (A) used in the present invention essentially contains a polyester polyol and a polyether polyol. More specifically, a crystalline polyester polyol (a-1) and a polyether polyol (a-2) obtained by a condensation reaction of an aliphatic dicarboxylic acid having 10 to 12 carbon atoms and an aliphatic diol having 4 to 6 carbon atoms. and mandatory.

The crystalline polyester polyol (a-1) according to the present invention is a polyol obtained by a condensation reaction between an aliphatic dicarboxylic acid having 10 to 12 carbon atoms and an aliphatic diol having 4 to 6 carbon atoms. Specifically, the aliphatic dicarboxylic acid (a-11) includes decanedioic acid (sebacic acid, C10), undecanedioic acid (C11) and dodecanedioic acid (C12). Aliphatic diols having 4 to 6 carbon atoms include butanediol (eg, 1,3-butanediol, 1,4-butanediol, etc.), pentanediol (eg, 1,5-pentanediol, etc.) and hexanediol. (eg, 1,6-hexanediol, etc.).

In the present invention, "crystalline polyester polyol" means a melting point of 30°C or higher, and "amorphous polyester polyol" means a melting point of 30°C or lower or absent. Such crystallinity can be adjusted by appropriately selecting the acid/glycol component. Here, using a differential scanning calorimeter, the melting peak in the range of -80°C to 100°C in a temperature program of 25°C to -80°C to 100°C (heating rate of 5°C/min) is defined as the melting point.

The crystalline polyester polyol (a-1) preferably has a number average molecular weight in the range of 1,000 to 5,000, more preferably in the range of 2,000 to 4,500.

Examples of the polyether polyol (a-2) include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc. obtained by polymerizing cyclic ethers such as ethylene oxide, propylene oxide and tetrahydrofuran, respectively, and copolyethers thereof. mentioned. It can also be obtained by polymerizing the above cyclic ether using a polyhydric alcohol such as glycerin or trimethylolethane.

The polyether polyol (a-2) preferably has a number average molecular weight within the range of 1,000 to 4,000, more preferably within the range of 1,500 to 3,000.

In addition, it is preferable to further contain one or more polyols selected from the group consisting of amorphous polyester polyols, polycarbonate polyols and low-molecular-weight diols having a number average molecular weight of 500 or less as other polyols (a-3).

Amorphous polyester polyols include, for example, aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid; Cyclic dicarboxylic acids such as hexahydrophthalic acid, hexahydroterephthalic acid and hexahydroisophthalic acid, or their acid esters or acid anhydrides with ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, Polyester polyols obtained by dehydration condensation reaction with 1,9-nonanediol or a mixture thereof; polylactone diols obtained by ring-opening polymerization of lactone monomers such as ε-caprolactone and methylvalerolactone;

Examples of polycarbonate polyols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexane. Diol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, at least one polyhydric alcohol such as an alicyclic dihydroxy compound, and diethylene Examples thereof include those obtained by reacting with carbonate, dimethyl carbonate, diethyl carbonate and the like.

The low-molecular-weight diol is not particularly limited as long as it has a number-average molecular weight of 500 or less. -propanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol.

Other polyols (a-3) may be used alone or in combination of two or more. In addition, other polyols (a-3) may contain polyols other than those described above.

Examples of the polyisocyanate (B) include tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), polymethylene polyphenyl polyisocyanate, hydrogenated MDI, 1,5-naphthalene diisocyanate, tolylene diisocyanate, 1 ,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, tetramethylxylene diisocyanate (TMXDI), 1,8-diisocyanatomethyloctane, lysine ester triisocyanate, 1,3 ,6-hexamethylene triisocyanate, 1,6,11-undecane triisocyanate, bicycloheptane triisocyanate, and modified products and derivatives thereof.

Polyisocyanate (B) may be used alone or in combination of two or more.

Although the NCO group content of the isocyanate-terminated polyurethane prepolymer is not particularly limited, it is preferably 1.0 to 2.5%. By setting the content in such a range, it is possible to promote curing due to moisture while suppressing foaming during operation. The NCO group content is measured according to JIS K1603-1.

The content of the polyurethane prepolymer is preferably 70-100% by mass (more preferably 80-100% by mass) relative to the entire composition.

・Other components As other components, known additives used in hot melt adhesives, such as oil components (plasticizers), tackifying resins, antioxidants, waxes, within the range of VOCs of 150 ppm or less etc. can be blended. In addition, heat stabilizers, fillers, catalysts, etc. may be blended.

Examples of oil components include paraffinic oils, naphthenic oils, and aromatic oils. In addition, you may use a vegetable oil etc. as an oil component.

Tackifying resins include aliphatic petroleum resins, aromatic petroleum resins, hydrogenated aliphatic petroleum resins, hydrogenated aromatic petroleum resins, terpene resins, styrene resins, rosin resins and modified resins thereof. One or more tackifying resins selected from the group consisting of can be exemplified.

Examples of antioxidants include phenolic antioxidants (e.g., Irganox 1010 (manufactured by BASF)), sulfur-based antioxidants (e.g., SUMILIZER TP-D (manufactured by Sumitomo Chemical Co., Ltd.)) and phosphorus-based antioxidants (e.g., , Irgafos 168 (manufactured by BASF), and JP-650 (manufactured by Johoku Kagaku)).

Waxes include natural waxes {e.g., animal waxes (beeswax, spermaceti, etc.), vegetable waxes (Japan wax, etc.), petroleum waxes (paraffin wax, etc.)}, and synthetic waxes {e.g., synthetic hydrocarbon waxes, etc.). (low molecular weight polyethylene etc.), fatty acid ester (polyethylene glycol etc.) etc.} can be exemplified.

Examples of catalysts include metal-based catalysts and amine-based catalysts. These catalysts may be used alone or in combination of two or more.

These additives may be used alone or in combination of two or more.

Here, the content of the crystalline polyester polyol (a-1) in the polyol component (A) is preferably 10 to 60 parts by mass with respect to 100 parts by mass of the polyol component (A). 40 parts by mass is more preferable. By setting it as such a range, it becomes possible to maintain an appropriate solidification time and high peel strength.

In addition, the content of the polyether polyol (a-2) in the polyol component (A) is 30 to 80 parts by mass, and may be 40 to 60 parts by mass, with respect to 100 parts by mass of the polyol component (A). preferred. By setting it as such a range, it becomes possible to achieve both high flexibility and peel strength.

The ratio of the content of the crystalline polyester polyol (a-1) to the content of the polyether polyol (a-2) in the polyol component (A) is preferably 20:80 to 70:30. and more preferably 30:70 to 50:50.

Furthermore, the content of the other polyol (a-3) in the polyol component (A) is preferably 30 parts by mass or less per 100 parts by mass of the polyol component (A). Such a range makes it possible to satisfy physical properties such as resistance to moist heat aging and peel strength. Although the lower limit is not particularly limited, it is, for example, 5 parts by mass with respect to 100 parts by mass of the polyol component (A).

≪Manufacturing method≫
The method for producing the moisture-curable hot-melt adhesive composition according to the present invention may be any known method, as long as the moisture-curable hot-melt adhesive composition produced does not impair the object of the present invention. Not limited.
For example, (1) a reaction vessel containing a predetermined amount of polyol is heated after dropping a predetermined amount of isocyanate, and the isocyanate groups of the polyisocyanate are reacted under conditions that are excessive with respect to the hydroxyl groups of the polyol. to prepare a polyurethane prepolymer. (2) A method of producing a desired moisture-curable hot-melt adhesive composition by dropping predetermined amounts of other components onto the polyurethane prepolymer and stirring the mixture. The reaction is carried out at a temperature of, for example, 50-120°C, preferably 60-100°C. The reaction time is, for example, 1 to 15 hours.

≪Physical properties≫
Next, each physical property of the hot-melt adhesive composition according to the present invention will be explained.

(VOC)
In the hot melt adhesive composition according to the present invention, the amount of organic volatile matter generated when heated at 90° C. is preferably 150 ppm or less in terms of toluene. By setting the VOC within this range, it is possible to satisfy the regulation value for all vehicle seat products. In order to adjust the VOC, it can be adjusted mainly by the type and amount of polyol/catalyst.

(Initial peel strength)
The hot-melt adhesive composition according to the present invention preferably has a peel strength of 1 N/25 mm or more (more preferably 1.3 N/25 mm or more) 30 seconds after laminating the urethane foam and the skin material. . The initial peel strength can be adjusted by adding an amorphous ester polyol, polycarbonate diol, or low molecular weight diol and controlling the amount added.

(Normal peel strength)
The hot-melt adhesive composition according to the present invention has a normal peel strength of 3 N/25 mm or more after one day of laminating the urethane foam and the skin material. In order to adjust the normal peel strength, the amount of crystalline ester polyol added and the type of other polyol components can be adjusted.

(solidification time)
The hot melt adhesive composition according to the present invention preferably has a solidification time of 6±4 minutes. If the solidification time is too long, a material with gaps such as a knitted fabric will be wound up before the adhesive is solidified, causing blocking due to seepage of the adhesive. Conversely, if it is too short, the adhesion to the substrate will be reduced, resulting in a reduction in normal peel strength. In order to adjust the solidification time, it is possible to adjust the addition amount of the crystalline ester polyol or control with a crystal nucleating agent.

(Damp heat resistance)
The hot-melt adhesive composition according to the present invention preferably maintains 80% strength from the normal peel strength for 400 hours or more at 80° C. 95% in moist heat resistance. In order to adjust the resistance to moist heat, the compatibility should be improved and the ester group concentration should be reduced.

≪Application≫
The hot-melt adhesive composition according to the present invention is a reactive hot-melt adhesive composition capable of laminating and adhering a skin material and a base material. In particular, it forms an adhesive layer (a layer made of a cured hot-melt adhesive composition) that is excellent in texture, air permeability, and permeation resistance when made into a specific fibrous form, which will be described later. Therefore, the skin material and base material can be applied regardless of the type, such as resin foam, resin film, synthetic leather, natural leather, woven fabric, or non-woven fabric. In addition, since it can also be applied to urethane resin foam as a base material, it can be applied to long products that laminate and bond a base material made of a continuous sheet and a skin material. It can also be used for vehicle interiors, which are difficult to apply.

≪How to apply≫
Next, an example of a method for applying the hot-melt adhesive composition according to the present invention will be described. In this example, the hot melt adhesive composition is applied using a non-contact method (for example, a spray method) so as to form a predetermined pressure-sensitive adhesive layer. The application method of the composition is not limited to this, and it may be applied to the adhesion target surface by a known method.

<Melting process>
First, the hot-melt adhesive composition according to the present invention is held in a molten state (melting step). If the hot-melt adhesive composition is moisture-curable, the melting process should be performed in a moisture-free atmosphere.

<Coating process>
Next, a hot-melt adhesive composition in a molten state is applied to the adherend target surface (preferably foam surface) of the adherend by an appropriate coating method (preferably a non-contact coating method). do. The specific shape at the time of application is not particularly limited, but for example, it may be applied in a linear shape, a dot shape, a fibrous shape, or the like to form an adhesive layer. Alternatively, the adhesive layer may be formed in a sheet shape. The amount of the adhesive composition applied to the adhesive layer is preferably 5 to 50 g/m ² (more preferably 10 to 30 g/m ² ). The adhesive composition may be applied to both surfaces to be adhered.

The specific coating conditions are not particularly limited. For example, when the non-contact coating method is used as described above, the pressure is 0.01 to 0.4 MPa, the temperature is 100 to 160 ° C., etc. good.

Here, the non-contact application method is a method of applying the adhesive composition without the application equipment coming into contact with the member to be adhered, and examples thereof include application by a spray method.

Prior to the coating step, the surface to be adhered may be subjected to a known pretreatment (for example, primer treatment, corona treatment, plasma treatment, etc.).

<Contact process, curing process>
After the application step, another member is brought into contact with the surface to be adhered (applied surface) provided with the adhesive layer, and the hot-melt adhesive composition is cooled and cured. In the case of a moisture-curable hot-melt adhesive composition, as described above, after cooling and curing, uncured isocyanate terminals react with moisture in the air to form a crosslinked structure, thereby exhibiting stronger adhesion. do.

When the hot-melt adhesive composition according to the present invention is applied by the method described in the application step, it can be adhered to any object to be adhered. Specifically, resin foams, resin films, synthetic leathers, natural leathers, woven fabrics, and non-woven fabrics are excellent in texture, air permeability, and adhesiveness, and can be prevented from permeating into the object to be adhered. In particular, even when the object to be adhered is a urethane resin foam, such an effect is obtained.

As described above, a laminate having an adhesive layer that is a cured product of the hot-melt adhesive composition according to the present invention, in particular, having a foam and an adhesive layer provided on the surface of the foam A laminate is obtained. As for the specific structure of the laminate, it is preferable that the laminate is composed of a urethane foam as a base material and a surface material or a backing base fabric. Such a laminate is preferably an interior material for a vehicle, that is, a base material {a cushioning layer made of foam, and a surface layer attached to the surface of a laminated sheet having a back base fabric layer formed on the back surface. It can be used as a laminated material (laminated sheet)}.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these.

≪Synthesis of urethane prepolymer≫
A predetermined polyol component (A) is put into a reactor, and diphenylmethane diisocyanate and an amine-based catalyst are added so as to be 0.05 parts by mass based on the total, and reacted at 100° C. for 3 to 4 hours. A urethane prepolymer having an NCO% of 2.0 was obtained.

<Polyol component (A)>
(Example 1)
Crystalline polyester polyol (sebacic acid/butanediol) melting point 60°C
Number average molecular weight 4000
35 parts by mass Polypropylene glycol Addition type PO alone Number average molecular weight 2000
50 parts by mass amorphous polyester polyol (phthalic acid/neopentyl glycol)
number average molecular weight 1000
15 parts by mass (Example 2)
Crystalline polyester polyol (dodecanedioic acid/hexanediol) melting point 70°C
Number average molecular weight 4000
35 parts by mass Polypropylene glycol Addition type PO alone Number average molecular weight 2000
50 parts by mass Polycarbonate diol Addition type PO alone Melting point 50°C
number average molecular weight 1000
15 parts by mass (Example 3)
Crystalline polyester polyol (dodecanedioic acid/hexanediol) melting point 70°C
Number average molecular weight 4000
35 parts by mass Polypropylene glycol Addition type PO alone Number average molecular weight 2000
50 parts by mass Butyl ethyl propanediol Addition form PO alone Melting point 43°C
15 parts by mass (Example 4)
Crystalline polyester polyol (dodecanedioic acid/hexandiol) Melting point 70°C
Number average molecular weight 4000
40 parts by mass polypropylene glycol addition type PO alone number average molecular weight 2000
30 parts by mass Butyl ethyl propanediol Melting point 43°C
30 parts by mass (Example 5)
Crystalline polyester polyol (sebacic acid/hexanediol) melting point 65°C
Number average molecular weight 4000
20 parts by mass polypropylene glycol addition form PO alone number average molecular weight 2000
80 parts by mass (Example 6)
Crystalline polyester polyol (sebacic acid/hexanediol) Melting point 70°C
number average molecular weight 10000
20 parts by mass polypropylene glycol addition form PO alone number average molecular weight 2000
80 parts by mass (Comparative Example 1)
Crystalline polyester polyol (adipic acid/butanediol) melting point 58°C
Number average molecular weight 2000
100 parts by mass (Comparative Example 2)
Crystalline polyester polyol (adipic acid/butanediol) melting point 58°C
Number average molecular weight 2000
30 parts by mass polypropylene glycol number average molecular weight 1000
70 parts by mass

≪Evaluation≫
Next, each hot-melt adhesive composition obtained above was specifically evaluated by the following methods. Table 1 shows the evaluation results. In the comprehensive evaluation, ○ if all evaluations satisfy the evaluation judgment value, VOC and moist heat resistance satisfy the evaluation judgment value, and △ if other evaluations do not satisfy the evaluation judgment value, VOC and moist heat resistance A case where at least one of the samples did not satisfy the evaluation judgment value was marked as x.

<VOC>
The hot-melt adhesive was directly put into a glass tube of a thermal desorption device (TD-100, Markes), and outgassing was measured by GC/MS (GC/MS (6890/5973), Agilent). The sample was heated at 90° C. for 30 minutes, and the values up to C20 were calculated in terms of toluene.

<Initial peel strength>
A urethane foam (150×25×5 mm) is spray-coated with a hot-melt adhesive melted at 140° C. at 20 g/m ² using a handgun (manufactured by REKA), and the surface material is crimped. After 30 seconds, a peeling test is performed at 200 mm/min using a digital force gauge DS2 (manufactured by IMADA), and the maximum value is N=3 and the median value is measured.

<Normal peel strength>
A urethane foam (150×25×5 mm) is spray-coated with a hot-melt adhesive melted at 140° C. at 20 g/m ² using a hand gun (manufactured by REKA), and the surface material is crimped. One day later, measurement was performed using an autograph (AG-Xplus manufactured by Shimadzu Corporation) at a tensile speed of 200 mm/min. A numerical value obtained by averaging the peel strengths of 3 points each of the maximum value and the minimum value was calculated as the median value of N=3.

<Solidation time>
15 g of a hot melt adhesive melted at 140° C. at an outside temperature of 25° C. is poured onto a glass plate, and a thin film of 500 μm thickness is formed with a film applicator with a micrometer (SA-204 manufactured by Tester Sangyo Co., Ltd.). The surface was touched with a finger to measure the time until the tack disappeared.

<Damp heat resistance>
A urethane foam (150×25×5 mm) is spray-coated with a hot-melt adhesive melted at 140° C. at 20 g/m ² using a hand gun (manufactured by REKA), and the surface material is crimped. After 3 days, it is allowed to stand in an environment of 80° C. and 95%, and the peel strength is measured every 100 hours. It was measured from the normal state peel strength to the time when 80% was maintained.

Claims (5)

A urethane hot-melt adhesive composition containing a urethane prepolymer made from a polyol component (A) and a polyisocyanate (B),
The polyol component (A) is a crystalline polyester polyol (a-1) having a number average molecular weight of 1000 or more, which is obtained by a condensation reaction of an aliphatic dicarboxylic acid having 10 to 12 carbon atoms and an aliphatic diol having 4 to 6 carbon atoms. , and a polyether polyol (a-2) having a number average molecular weight of 1000 or more,
The polyol component (A) further contains one or more polyols selected from the group consisting of amorphous polyester polyols and diols having a molecular weight of 500 or less,
A urethane hot melt adhesive characterized in that the content of the polyether polyol (a-2) in the polyol component (A) is 30 to 80 parts by mass with respect to 100 parts by mass of the polyol component (A). Compositions (excluding those containing an acrylic polyol as the polyol component (A) and those containing an acrylic copolymer in the urethane hot-melt adhesive composition). A urethane hot-melt adhesive composition containing a urethane prepolymer made from a polyol component (A) and a polyisocyanate (B),
The polyol component (A) comprises a crystalline polyester polyol (a-1) obtained by a condensation reaction of an aliphatic dicarboxylic acid having 10 to 12 carbon atoms and an aliphatic diol having 4 to 6 carbon atoms, and a polyether polyol (a- 2) containing
The polyol component (A) includes ethylene glycol, propanediol, 2-methyl - 1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5- further containing one or more polyols selected from the group consisting of pentanediol and 2-ethyl-1,3-hexanediol;
A urethane hot melt adhesive characterized in that the content of the polyether polyol (a-2) in the polyol component (A) is 30 to 80 parts by mass with respect to 100 parts by mass of the polyol component (A). Composition. 3. The urethane hot-melt adhesive composition according to claim 1, wherein the amount of organic volatile matter generated when heated at 90[deg.] C. is 150 ppm or less in terms of toluene. 4. The urethane hot-melt adhesive composition according to any one of claims 1 to 3 , which is used for vehicle members comprising foam, natural leather, synthetic leather, film, woven fabric or non-woven fabric. The urethane hot-melt adhesive composition according to any one of claims 1 to 4 , which is for application by a spray method.