JP5964098B2 - Method for producing semi-rigid polyurethane foam for automobile interior materials - Google Patents

Description

  The present invention relates to a method for producing a semi-rigid polyurethane foam suitable for automobile interior materials such as instrument panels.

  Polyurethane foam is obtained by reacting polyols and isocyanate in the presence of a foaming agent and a catalyst, and is often used for bedding, automobile interior materials, and the like.

  Polyurethane foams include soft polyurethane foams, rigid polyurethane foams, and semi-rigid polyurethane foams located in the middle. Since semi-rigid polyurethane foams have good shock absorption, they are often used for automotive interior materials such as instrument panels. It is used.

In recent years, polyurethane foams using plant-derived polyols have been developed from the viewpoint of reducing environmental impact.
Patent Document 1 proposes a polyurethane foam for automobile seats using castor oil polyol as a plant-derived polyol.

Patent Document 2 discloses a method for producing a polyurethane foam using a castor oil polyol having a terminal hydroxyl group of secondary or tertiary and a hydroxyl value of 20 to 350 mgKOH / g in order to improve resistance to moist heat aging. .
Patent Document 3 discloses a method for producing a vibration-absorbing and sound-absorbing material made of polyurethane foam using a castor oil polyol as a polyol.
Patent Document 4 discloses a method for producing a polyurethane foam for automobile interior materials by mixing and reacting a plant-derived polyol, a polyether polyol containing a tertiary amino group, water, a catalyst, a foam stabilizer and a polyisocyanate. Has been.

  However, in the conventional method for producing a polyurethane foam using a plant-derived polyol (including castor oil polyol), the demolding time at the time of molding is longer than that in the case of using a normal polyol, and the work efficiency becomes poor and the expensive There is a problem that a molecular weight amine polyol is required and the cost is increased. Mold molding is a molding method in which a polyurethane material is filled in a mold (mold) and foamed, and then the foam is removed from the mold. The mold molding is frequently used in the production of urethane foam used for automobile interior materials and the like.

JP 2005-320437 A JP 2008-019353 A JP 2008-274092 A JP 2011-0668719 A

  The present invention has been made in view of the above points, and a semi-rigid polyurethane foam for automobile interior materials using a castor oil polyol derived from a plant can be demolded at low cost and in a short time using conventional general-purpose raw materials. It aims at providing the manufacturing method which can be performed.

The invention according to claim 1 is a process for producing a semi-rigid polyurethane foam for automobile interior materials, in which a polyurethane raw material containing a polyol, a polyisocyanate, a catalyst, a foaming agent and a foam stabilizer is filled in a mold and foam-cured. the, at least, a hydroxyl value 150 to 280 mg KOH / g, and castor oil polyol with a number average molecular weight of 600 to 1000, and polyether polyol having a hydroxyl value 15~100mgKOH / g, number average molecular weight 8,000, hydroxyl value 20~50mgKOH / G, a polymer polyol having a number average molecular weight of 3000 to 6000, and the polyether polyol has a ratio of ethylene oxide to propylene oxide of 10:90 to 15:85 , based on 100 parts by mass of the polyols The castor oil polio 1 to 40 parts by mass of the polyol, 30 to 80 parts by mass of the polyether polyol, 15 to 30 parts by mass of the polymer polyol, water as the blowing agent, and polymeric MDI as the polyisocyanate. And

According to the present invention, as polyols, at least, a hydroxyl value 150 to 280 mg KOH / g, number and castor oil polyol having an average molecular weight 600 to 1000, a hydroxyl value 15~100mgKOH / g, number average polyether polyol having a molecular weight of 2,000 to 8,000 And a polymer polyol having a hydroxyl value of 20 to 50 mgKOH / g and a number average molecular weight of 3000 to 6000, the polyether polyol has a ratio of ethylene oxide to propylene oxide of 10:90 to 15:85, polyols per 100 parts by weight, the castor oil polyol 1-40 parts by weight, the polyether polyol from 30 to 80 weight parts, by including the polymer polyol 15 to 30 parts by weight, balanced reaction, the polyol used in combination with castor oil polyol Without using an expensive polyol, it is possible to produce a semi-rigid polyurethane foam suitable for automotive interior materials in a short demolding time.

  The method for producing a semi-rigid polyurethane foam for automobile interior materials in the present invention is obtained by mixing and stirring a polyurethane raw material containing polyols, polyisocyanate, catalyst, foaming agent and foam stabilizer, filling the mold, and foam-curing it. The foam is removed from the mold, and is suitable for the manufacture of instrument panels, armrests, door trims, and the like. Note that insert molding in which a skin, a base material, and the like are set in advance on the inner surface of the mold is also included in the production method of the present invention. Moreover, the definition of the semi-rigid polyurethane foam suitable for automobile interior materials in the present invention is as follows. The tensile strength based on JIS K 6400-5: 2004 is 300 to 800 kPa (dumbbell No. 2), and the elongation is 30 to 150% (dumbbell). No. 2), a urethane foam having a tear strength of 10 to 25 N / cm (No. 4 type test piece) and a Japan Rubber Association Standard (SRIS) 0101 (Asker C type) hardness of 20 to 65.

As the polyols used in the present invention, three types of castor oil polyol, polyether polyol and polymer polyol are used in combination.
The castor oil polyol has a semi-rigid polyurethane foam having a medium hardness (20 to 65) and a small distortion, so that the hydroxyl value (OHV) is 40 to 350 mgKOH / g, the number average molecular weight is 400 to 3200, and the number of functional groups is 2 to 6. Is selected. Further, those having a hydroxyl value of 100 to 300 mgKOH / g, a number average molecular weight of 550 to 1500 and a functional group number of 2 to 4 are more preferred, and a hydroxyl value of 150 to 280 and a number average molecular weight of 600 to 1000 are particularly preferred. The compounding amount of the castor oil polyol is preferably 1 to 40 parts by mass in 100 parts by mass of the polyols. When the amount is less than 1 part by mass, the usage cost of castor oil polyol is small and the effect of reducing the environmental load is reduced. On the other hand, when the amount is more than 40 parts by mass, voids and sink marks are produced in the molded product.

  The polyether polyol is obtained by addition polymerization of alkylene oxide using a polyhydric alcohol or the like as an initiator, and in the present invention, castor oil polyol is excluded. The polyhydric alcohol is bifunctional, such as propylene glycol, ethylene glycol, etc., trifunctional, glycerin, trimethylolpropane, etc., and tetrafunctional, such as pentaerythritol, hexitol, sorbitol, Sucrose etc. can be mentioned as an octafunctional thing. The polyether polyol preferably has a hydroxyl value (OHV) of 15 to 100 mgKOH / g, a number average molecular weight of 2000 to 8000, and a functional group number of 2 to 4, more preferably a hydroxyl value of 25 to 60 mgKOH / g, a number average molecular weight. The thing of 2000-8000 and 2-3 functional groups is more preferable. Further, the polyether polyol preferably has a ratio of ethylene oxide (EO) to propylene oxide (PO) of 5:95 to 30:70, more preferably 10:90 to 15:85. As for the compounding quantity of the said polyether polyol, 25-80 mass parts is preferable in 100 mass parts of the said polyols, More preferably, it is 30-80 mass parts. If the amount is less than 25 parts by mass, castor oil polyol or polymer polyol becomes excessive, causing sink marks and voids in the molded product. On the other hand, if the amount is more than 80 parts by mass, will the amount of castor oil polyol be reduced? The amount of polymer polyol added is insufficient, and the tensile strength, tear strength, and hardness are reduced.

  The polymer polyol is preferably a polyether polyol obtained by polymerizing styrene or acrylonitrile, or styrene and acrylonitrile. The ratio of styrene and acrylonitrile is preferably 0/100 to 50/50. The polymer polyol preferably has a hydroxyl value (OHV) of 20 to 50 mgKOH / g, a number average molecular weight of 3000 to 6000, and a functional group number of 2 to 4, particularly a hydroxyl value of 20 to 40 mgKOH / g, a number average molecular weight of 4000 to 6000, and a functional group number. A few are more preferable. As for the compounding quantity of the said polymer polyol, 10-35 mass parts is preferable in 100 mass parts of the said polyols, More preferably, it is 15-30 mass parts. When the amount is less than 10 parts by mass, the tensile strength, tear strength, and hardness are reduced. On the other hand, when the amount is more than 35 parts by mass, sink marks and voids are formed in the molded product.

  The polyisocyanate includes polymeric MDI (polymethylene polyphenylene polyisocyanate). Polymeric MDI is an isocyanate widely used in a method for producing urethane foam. In the present invention, a semi-rigid polyurethane foam can be produced at low cost also by using a general-purpose polymeric MDI. Note that the polyisocyanate in the present invention is not limited to polymeric MDI, and may contain polymeric MDI. MDI, TD1, etc. may be used in combination, but only polymeric MDI is used. Particularly preferred.

  The blending amount of the polyisocyanate is preferably such that the isocyanate index (INDEX) is 95 to 120. When the isocyanate index is less than 95, the tensile strength, tear strength, and hardness are reduced. On the other hand, when it exceeds 120, brittleness is developed and the tear strength is reduced. The isocyanate index is a value indicating the equivalent ratio of the isocyanate group of the polyisocyanate as a percentage with respect to the total of active hydrogen groups in the polyurethane raw material (for example, active hydroxyl groups such as polyol hydroxyl groups and water used as a blowing agent). It is an indicator used in the field of polyureta foam.

  As the foaming agent, those known for polyurethane foam can be used. For example, water, pentane, cyclopentane, hexane, cyclohexane, dichloromethane, carbon dioxide gas or the like is used, and water is particularly preferable. The blending amount of the foaming agent is an appropriate amount, but in the case of water, it is usually about 1 to 3 parts by mass with respect to 100 parts by mass of the polyols.

  As the catalyst, those known for polyurethane foam can be used, and are not particularly limited. Examples of usable catalysts include amine catalysts such as triethylamine, triethylenediamine, and tetramethylguanidine, tin catalysts such as dibutyltin dilaurate and stannous octoate, and metal catalysts such as phenylmercurypropionate and lead octenoate ( Also referred to as an organometallic catalyst.). Although the compounding quantity of a catalyst is suitably determined by the kind of catalyst, about 0.3-4.0 mass parts is common with respect to 100 mass parts of polyols.

  As the foam stabilizer, those known for polyurethane foams can be used, and examples thereof include silicone foam stabilizers, fluorine-containing compound foam stabilizers and surfactants. In particular, silicone foam stabilizers are suitable. Silicone foam stabilizers include those composed mainly of siloxane chains, siloxane chains and polyether chains having a linear structure, branched and branched, and polyether chains modified in a pendant form to siloxane chains. Etc.

  The polyurethane raw material is appropriately mixed with an auxiliary agent. Examples of the auxiliary agent include a chain extender, a colorant, a flame retardant, an antibacterial agent, a stabilizer, and a plasticizer. Examples of the chain extender include, for example, low molecular weight polyhydric alcohols such as ethylene glycol, 1,4-butanediol, and glycerin, low molecular weight amine polyols such as diethanolamine and triethanolamine, or ethylenediamine, xylylenediamine, And polyamines such as methylenebisorthochloroaniline.

  The injection of the polyurethane raw material into the mold is performed using a known injection device (low pressure injection device, high injection device). Also, the injection of the polyurethane raw material into the mold is performed by injecting the mold in an open state and then closing the mold or by injecting from the injection port formed in the mold with the mold closed. Either may be sufficient.

Examples and comparative examples are specifically shown below, but the present invention is not limited to these examples.
Using a high-pressure molding machine (PU-30 manufactured by PEC Co.), 480 g of a polyurethane raw material having the composition shown in Tables 1 to 5 to be described later is filled into a prototype 300 × 1000 × 10 mm rectangular mold, and thereafter By removing the mold, a semi-rigid polyurethane foam for automobile interior parts was molded. The raw materials used are as follows.
(1) Castor oil polyol 1: hydroxyl value 32 mgKOH / g, number average molecular weight 3510, average number of functional groups 2
(2) Castor oil polyol 2: hydroxyl value 50 mgKOH / g, number average molecular weight 3000, average functional group number 2.7
(3) Castor oil polyol 3: hydroxyl value 160 mgKOH / g, number average molecular weight 950, average functional group number 2.7
(4) Castor oil polyol 4: hydroxyl value 270 mgKOH / g, number average molecular weight 620, average number of functional groups 3
(5) Castor oil polyol 5: hydroxyl value 340 mgKOH / g, number average molecular weight 500, average number of functional groups 3
(6) Polyether polyol 1: hydroxyl value 28 mgKOH / g, number average molecular weight 8000, average functional group number 4
(7) Polyether polyol 2: hydroxyl value 33 mgKOH / g, number average molecular weight 5000, average functional group number 3
(8) Polyether polyol 3: hydroxyl value 29 mgKOH / g, number average molecular weight 4000, average number of functional groups 2
(9) Polyether polyol 4: hydroxyl value 56 mgKOH / g, number average molecular weight 2000, average functional group number 2
(10) Polyether polyol 5: hydroxyl value 102 mg KOH / g, number average molecular weight 1100, average functional group number 2
(11) Polymer polyol 1: hydroxyl value 43 mgKOH / g, number average molecular weight 3000, average number of functional groups 3, styrene / acrylonitrile ratio 50:50, polymer content 26%
(12) Polymer polyol 2: hydroxyl value 28 mgKOH / g, number average molecular weight 5000, average functional group number 2.7, styrene / acrylonitrile ratio 0: 100, polymer content 20%
(13) Polymer polyol 3: hydroxyl value 21 mgKOH / g, number average molecular weight 6000, average number of functional groups 3, styrene / acrylonitrile ratio 50:50, polymer content 40%
(14) Chain extender 1: tertiary amine polyol having a hydroxyl value of 795 mg KOH / g, number average molecular weight 350, average functional group number 5
(15) Catalyst 1: dipropylene glycol solution containing 33% TEDA having a hydroxyl value of 989 mgKOH / g, product number: DABCO 33LV, manufactured by Sankyo Air Products Co., Ltd. (16) Catalyst 2: bis (dimethylaminoethyl) having a hydroxyl value of 251 mgKOH / g ) Ether, product number: Kaoriza No. 12P, Kao Corporation (17) Foaming agent: water All polyisocyanates used were general-purpose polymethylene polyphenylene polyisocyanate (polymeric MDI).

  In the following table, voids are large bubbles generated in the foaming process, and the foam after demolding is visually determined on one side of the foam surface 300 × 1000 mm after molding, and the case where there are many voids ×, 10 to 10 The case where there were 20 pieces was marked as △, the case where there were several pieces as ◯, and the case where there were none as ◎. Sink marks are dents that occur on the foam surface due to shrinkage after foaming, and the foam surface after demolding is visually judged. If it occurs in 30% or more of the outer periphery, ×, if generated, 30% or less In the case of △, the case where it did not occur was marked as ◯. On the other hand, the curing time was basically 1 minute, and when curing was insufficient and it was difficult to remove the mold, the curing time was 8 minutes and measured with a stopwatch. Further, the polyurethane foam after demolding was measured with dumbbell No. 2 for tensile strength and elongation based on JIS K 6400-5: 2004, and tear strength was measured with No. 4 test piece. The hardness (Asker C) was measured according to the Japan Rubber Association Standard (SRIS) 0101 (Asker C type).

Reference Examples 1 to 4 in Table 1 are examples in which the polyols do not contain castor oil polyol. Moreover, the comparative examples 1-5 of Table 1 and Table 2 are examples from which the quantity of a castor oil polyol remove | deviates from this invention.
On the other hand, Reference Example 1a and Examples 2-3 in Table 2 are examples in which the amounts of castor oil polyol 3, polyether polyol 2, polyether polyol 3, and polymer polyol 2 were changed within the scope of the present invention. Specifically, Reference Example 1a is an example in which castor oil polyol 3 is 40 parts by mass, polyether polyol 3 is 25 parts by mass, and polymer polyol 2 is 35 parts by mass. Example 2 is the polyether in Reference Example 1a . In this example, the polyol 2 is changed from 0 to 20 parts by mass, the polyether polyol 3 is reduced from 25 parts by mass to 20 parts by mass, and the polymer polyol 2 is reduced from 35 parts by mass to 20 parts by mass. In Example 3, castor oil polyol 3 in Reference Example 1a was reduced from 40 parts by weight to 25 parts by weight, polyether polyol 2 was reduced from 0 to 30 parts by weight, and polymer polyol 2 was reduced from 35 parts by weight to 20 parts by weight. It is.

Comparative Example 6 in Table 3 is an example using castor oil polyol 1 whose hydroxyl value and number average molecular weight deviate from the range of the present invention, and Comparative Example 7 is an example in which the amount of castor oil polyol is larger than the range of the present invention. On the other hand, Reference Example 4a, Example 5, Example 6, and Reference Example 7 in Table 3 are examples in which the type and amount of castor oil polyol were varied. Specifically, Reference Example 4a is an example in which castor oil polyol 2 is used instead of castor oil polyol 3 of Example 2 and the curing time is 8 minutes. In Example 5, castor oil polyol 2 of Example 2 is reduced from 40 parts by mass to 25 parts by mass, polyether polyol 2 is increased from 20 parts by mass to 30 parts by mass, and polyether polyol 3 is increased from 20 parts by mass to 25 parts by mass. This is an example of the increase. Example 6 is an example in which castor oil polyol 4 was used in place of castor oil polyol 3 of Example 2. Reference Example 7 is an example in which castor oil polyol 5 was used instead of castor oil polyol 3 of Example 2.

Example 8 , Reference Example 9, Example 10, Reference Example 11, and Example 12 in Table 4 are examples in which the amount of the polyether polyol and the kind and amount of the polymer polyol of Example 2 were changed. Specifically, in Example 8, both polyether polyol 2 and polyether polyol 3 of Example 2 were reduced from 20 parts by mass to 15 parts by mass, and 30 parts by mass of polymer polyol 1 was used instead of polymer polyol 2. It is an example. In Reference Example 9 , the polyether polyol 2 of Example 2 was reduced from 20 parts by mass to 10 parts by mass, the polyether polyol 3 was reduced from 20 parts by mass to 15 parts by mass, and the polymer polyol 2 was reduced from 20 parts by mass to 35 parts by mass. This is an example of the increase. Example 10 is an example in which the polyether polyol 2 and the polyether polyol 3 of Example 2 are both reduced from 20 parts by mass to 15 parts by mass, and the polymer polyol 2 is increased from 20 parts by mass to 30 parts by mass. Reference Example 11 is an example in which both polyether polyol 2 and polyether polyol 3 of Example 2 were increased from 20 parts by weight to 25 parts by weight, and polymer polyol 2 was reduced from 20 parts by weight to 10 parts by weight. Example 12 is an example in which the polyether polyol 2 and the polyether polyol 3 of Example 2 were both reduced from 20 parts by mass to 15 parts by mass, and 30 parts by mass of the polymer polyol 3 was used instead of the polymer polyol 2.

Examples in Table 5 are examples in which castor oil polyol, polyether polyol, and polymer polyol were changed within the scope of the present invention. Specifically, Example 13 and Example 14 are examples in which the amounts of castor oil polyol 3, polyether polyol 1, and polymer polyol 2 were changed. Example 10, Example 2 and Example 15 are examples in which the amounts of castor oil polyol 3, polyether polyol 2, polyether polyol 3 and polymer polyol 2 were changed. Examples 16 and 17 are examples in which the amounts of castor oil polyol 3, polyether polyol 4 and polymer polyol 2 were changed.
On the other hand, Comparative Example 8 in Table 5 is an example using a polyether polyol 5 whose hydroxyl value and number average molecular weight are outside the scope of the present invention.

The semi-rigid polyurethane foams of Reference Examples 1 to 4 have a short curing time, no voids and sink marks, and are suitable for automobile interior materials, but since castor oil polyol is not used, from the viewpoint of reducing the global environmental load. It is inferior.
Semi-rigid of Reference Example 1a, Examples 2-3 , Reference Example 4a, Example 5, Example 6, Reference Example 7, Example 8 , Reference Example 9, Example 10, Reference Example 11, and Examples 12-17 Polyurethane foams are all suitable for automobile interior materials with a short curing time, few voids and sink marks, and because castor oil polyol is used, they are also excellent from the viewpoint of reducing environmental impact. In Reference Example 4a, when the curing time was 1 minute, the foam adhered to the mold and it was difficult to remove the mold, so the curing time was 8 minutes.

  On the other hand, neither Comparative Example 1 nor Comparative Example 2 in which the polyols were 100% castor oil polyol produced a foam due to poor reaction. Further, Comparative Example 3, Comparative Example 4 and Comparative Example 5 in which the amount of castor oil polyol deviated from the scope of the present invention had many voids and large sink marks, and could not be used as a product. Furthermore, Comparative Example 3 and Comparative Example 4 in which the amount of castor oil polyol is larger than the range of the present invention is inferior in productivity because the curing time is as long as 8 minutes and demolding takes time.

  Moreover, the comparative example 6 which uses the castor oil polyol 1 in which a hydroxyl value and a number average molecular weight remove | deviate from the range of this invention did not become foam by reaction failure. Since Comparative Example 7 in which the amount of castor oil polyol 3 was larger than the range of the present invention had many voids and large sink marks, it could not be used as a product. Further, Comparative Example 8 using the polyether polyol 5 whose hydroxyl value and number average molecular weight deviate from the scope of the present invention was not usable as a product because of many voids and large sink marks.

  As described above, the method for producing a semi-rigid polyurethane foam for automobile interior material according to the present invention can remove a semi-rigid polyurethane foam at low cost and in a short time using a castor oil polyol derived from a plant and a conventional general-purpose raw material. Can be produced and has the effect of improving productivity.

Claims (1)

In a method for producing a semi-rigid polyurethane foam for automobile interior materials, in which a polyurethane raw material containing a polyol, a polyisocyanate, a catalyst, a foaming agent and a foam stabilizer is filled in a mold and foamed and cured,
The said polyols, at least, a hydroxyl value 150 to 280 mg KOH / g, number and castor oil polyol having an average molecular weight 600 to 1000, and polyether polyol having a hydroxyl value 15~100mgKOH / g, number average molecular weight 8,000, hydroxyl value In combination with 20 to 50 mg KOH / g, a polymer polyol having a number average molecular weight of 3000 to 6000,
The polyether polyol has a ratio of ethylene oxide to propylene oxide of 10:90 to 15:85,
1 to 40 parts by mass of the castor oil polyol, 30 to 80 parts by mass of the polyether polyol, and 15 to 30 parts by mass of the polymer polyol with respect to 100 parts by mass of the polyols,
Including water as the blowing agent;
A method for producing a semi-rigid polyurethane foam for automobile interior materials, comprising polymeric MDI as the polyisocyanate.