JPH07307B2 - Polyurethane foam product with different hardness and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a molded article of an elastic polyurethane foam, and more particularly to a different hardness foam having different hardness depending on a part and a method for producing the same.

(Prior Art) Elastic polyurethane foam is used in almost all automobiles as seats, back cushions, headrests, etc. Recently, along with the speeding up of automobiles, it has become necessary to use these cushioning materials to enhance the retention of the body of the driver and passengers. As a countermeasure against this, metal wires and chip foams have been put in the embankments on both sides of the seat and backrest. If a metal wire is used, the weight and the manufacturing cost are increased, and if the metal wire is crushed to improve the air permeability after manufacturing the foam, the metal wire may be deformed. Further, when the chip foam is used, a feeling of foreign matter is generated on the surface of the foam and the feeling is deteriorated. In addition, the manufacturing process becomes complicated.

(Problems to be Solved by the Invention) In order to solve these problems, in JP-A-57-145620, a plurality of mixing heads are used, and a foaming stock solution having a different composition is simultaneously injected into a predetermined portion of a mold. A method has been developed in which foaming is used to increase the hardness only in the seat and the bank portion of the backrest or to manufacture a different hardness foam. In this method, it is necessary to inject a plurality of stock solutions having different formulations at the same time, so that the number of tanks, pipes, mixing heads, etc. is increased and the equipment cost is significantly increased. Further, since the positions of the contact surfaces of the foams having different hardnesses are not constant, there is a problem in that the quality of the manufactured products having different hardnesses is different.

(Means for Solving Problems) As a result of various investigations by the present inventors in order to solve the above problems, good results can be obtained by using a slab foam that has already been foam-cured as a component of a different hardness foam. And have completed the present invention.

That is, the present invention is: (1) A polyurethane foam consisting of parts having different hardnesses, and parts 1, 21, 31, 41 are slab foams having a specific hardness that has already been foamed and cured,
The remaining portions 2, 22, 32, 42 are molding foams having different hardness formed by injecting the polyurethane foam raw material mixture and foam-molding integrally with the slab foam, and the boundary surface 3, 23 between the slab foam and the molding foam. 33, 43, a different hardness polyurethane foam molded article, wherein the thickness of the hardness increasing portion due to impregnation is 1 to 3 mm.

(2) Different hardness polyurethane foam molding characterized in that the polyurethane foam raw material mixture to be injected into the remaining portions 2, 22, 32, 42 has a cream time of 3 to 8 seconds and a rise time of 20 to 70 seconds. It is a method of manufacturing a product.

The polyurethane foam raw material mixture used in the present invention is 1
Since it is a type, the number of tanks, pipes, mixing heads, etc. can be saved, so that the equipment cost can be reduced, and the molding operation can be simplified and stabilized. Further, since the position of the boundary surface between the slab foam and the forming foam is fixed, the quality of the generated different hardness foam becomes constant.

In the present invention, the hardness of the slab foam is different from that of the molding foam, but either one may be higher depending on the portion used. Further, the slab foam may use two or more kinds having different hardness. The hardness of the different hardness polyurethane foam molding is 10 to 30 kg / 314 cm in the center of the seat and backrest, respectively.
² and within the range of 5 to ²⁰ kg / 314 cm ² . The hardness of the banks on both sides is 15 to 50 kg / 314 cm ² and 10 to 50 kg / 31.
Be within the range of 4 cm ² . If the hardness is out of this range, the riding comfort becomes poor and the body retainability deteriorates.

Also, when the injected polyurethane foam raw material mixture foams, it penetrates into the surface of the slab foam and after hardening, the hardness of this portion increases. If the depth of penetration is 1 to 3 mm, there is no problem in practical use, but if it exceeds this, a foreign-body sensation is produced in the different hardness polyurethane foam molded product. 1mm again
If it is less than the above, the adhesive strength of the interface decreases. Therefore, in order to stop the penetration depth to 11 to 3 mm, it is necessary to set the cream time of the injected polyurethane foam raw material mixture to 3 to 8 seconds and the rise time to 20 to 70 seconds. If the cream time and the rise time exceed this range, the increase in the viscosity of the raw material mixture is delayed, and as a result, the penetration depth increases and the hardness significantly increases. On the other hand, when the amount is less than this range, the raw material mixture is hardened before entering the slab foam, so that the adhesive strength of the interface decreases.

Next, the present invention will be described with reference to the drawings.

Figure 1 shows the slab foam 1 attached to the top of the seat,
The other part is a sectional view of a seat made of a polyurethane foam of different hardness, which is composed of a molding foam 2 obtained by injecting a polyurethane foam raw material mixture into a mold and foaming and curing the mixture.

FIG. 2 is a sectional view of a seat made of a polyurethane foam of different hardness in which the entire seat portion is composed of the slab foam 21, and the entire bank portions on both sides are composed of the molding foam 22 formed by injecting and foaming the raw material mixture.

FIG. 3 is a cross-sectional view of a seat made of a different hardness polyurethane foam in which a slab foam 31 is placed under the bank portions on both sides and the other portions are formed by molding foam 32 obtained by injection foaming.

FIG. 4 is a cross-sectional view of a headrest made of a polyurethane foam of different hardness, the outer side of which is formed of a slab foam 41 and the inner side of which is formed by molding foam 42 obtained by injection foaming.

1-4, 3, 23, 33, and 43 show boundary surfaces.

The polyol used in the present invention is water, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, trimethylene glycol, 1,3- and 1,4-butanediol,
1,5-pentanediol, glycerin, 1,2,6-hexanetriol, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, pentaerythritol, sorbit, sucrose, lactose, α -Methyl glucoside, novolac resin, polyhydric hydroxy compounds such as phosphoric acid, polyphosphoric acid, aniline, ethylenediamine, diethylenetriamine, triethylenetetramine, methyleneorthochloraniline, 4,4'-diphenylmethanediamine, 2,4-tolylenediamine Obtained by adding one or more of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide and the like to amines such as 2,2,6-tolylenediamine and alkanolamines such as triethanolamine and diethanolamine. Polyether polyols Or polytetramethylene ether glycol. In addition, ethylene glycol, diethylene glycol, triethylene glycol,
Propylene glycol, dipropylene glycol, trimethylene glycol, 1,3 and 1,4-butanediol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, decamethylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbit, etc. One or more compounds having at least two hydroxyl groups, and malonic acid, maleic acid, succinic acid, adipic acid, plastic acid, pimelic acid, sebacic acid, oxalic acid, phthalic acid, triterephthalic acid Also used are ring-opening polymers of polyester polyols obtained from one or more compounds having at least two carboxyl groups such as mellitic acid and hemi-mellitic acid, or cyclic esters such as polycaprolactone. Furthermore, Japanese Patent Publication 39-24737, Japanese Publication 41-3473, Japanese Publication 43-22108, Japanese Publication 4
4-8230, JP-B-47-47597, JP-B-47-47999, JP-A-48-3
4991, JP-A-51-50398, JP-A-51-70286, JP-A-52-112
49, JP-A-53-4092, JP-A-53-4092, JP-A-53-13700,
JP-A-54-64264, JP-A-53-78297, JP-A-54-133599,
A so-called polymer polyol composition obtained by graft-polymerizing an ethylenically unsaturated compound in the polyether polyol and / or polyester polyol described in JP-A-55-5988 is used. Suitable ethylenically unsaturated compounds for preparing such compositions include acrylonitrile, styrene and the like. Further, 1,2-polybutadiene polyol and 1,4-polybutadiene polyol are also used.

Among these polyols, a polyol particularly suitable for the present invention is a 2- to 4-functional polyether polyol obtained by addition-polymerizing propylene oxide and ethylene oxide, and the content of ethylene oxide in the total alkylene oxide is 10%. .About.20% by weight, and the content of primary hydroxyl group at the terminal is 50 to 90% by weight. Further, a polymer polyol obtained by graft-polymerizing acrylonitrile or acrylonitrile and styrene to this polyol is also suitable for the present invention.

The preferred range of hydroxyl number for the various polyols mentioned above is 20 to 150 mg KOH / g, and these polyols may be used alone or as a mixture.

The polyisocyanate used in the present invention is, for example, 2,4-
Tolylene diisocyanate, 2,6-tolylene diisocyanate, 80/20 weight ratio of both these isocyanates (80 / 20-T
DI) or a mixture of 65/35 weight ratio (65 / 35-TDI), crude tolylene diisocyanate (crude TDI), 4,4'-difermethane diisocyanate (4,4'-MDI), 2,4'- Difermethane diisocyanate (2,4'-MDI), 2,2'-
Difermethane diisocyanate (2,4'-MDI), diphenylmethane diisocyanate isomer mixture (MD
I), polymethylene polyphenyl polyisocyanate (crude MDI), toluidine diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and carbodiimide modified products, burette modified products, dimers, and tris of these isocyanates. It is a polymer and a prepolymer.

Polyisocyanates may be used alone or as a mixture,
A particularly suitable polyisocyanate for the present invention is a mixture of carbodiimide modified isomers of diphenylmethane diisocyanate with polymethylene polyphenyl polyisocyanate.

Crosslinked strings used in the present invention include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, trimethylene glycol, monomer polyols such as 1,3- and 1,4-butanediol, triethanolamine. , Alkanolamines such as diethanolamine, aliphatic diamines such as ethylenediamine, diethylenetriamine and triethylenetetramine, methyleneorthochloramine,
Aromatic polyamines such as 4,4'-diphenylmethanediamine, aniline, 2,4-tolylenediamine, 2,6-tolylenediamine, etc. and ethylene oxide, propylene oxide, etc. added to these active hydrogen compounds. A compound having a hydroxyl value of 200 mgKOH / g or more.

In addition, a compound having a hydroxyl value of 200 mgKOH / g or more obtained by adding ethylene oxide and / or propylene oxide to hydroquinone, resorcin, aniline or the like can also be used.

The polyisocyanate, the polyol and the crosslinking agent are used so that the equivalent ratio (NCO / H) of the NCO group in the polyisocyanate to the active hydrogen in the polyol and the crosslinking agent is 0.70 to 1.40.

The catalyst that can be used in the present invention is conventionally known and is not particularly limited. For example, amine-based urethane-forming catalysts (triethylamine, tripropylamine, triisopropanolamine, tributylamine, trioctylamine, hexadecyldimethylamine, N -Methylmorpholine, N
-Ethylmorpholine, N-octadecylmorpholine, monoethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N, N-dimethylethanolamine, diethylenetriamine, N, N,
N ', N'-tetramethylethylenediamine, N, N, N', N '
-Tetramethylpropylenediamine, N, N, N ', N'-tetramethylbutanediamine, N, N, N', N'-tetramethyl-1,3-butanediamine, N, N, N ', N' -Tetramethylhexamethylenediamine, bis [2- (N, N-dimethylamino) ethyl] ether, N, N-dimethylbenzylamine, N, N-dimethylcyclohexylamine, N, N, N ',
N ", N" -pentamethyldiethylenetriamine, triethylenediamine, triethylenediamine formate and other salts, oxyalkylene adducts of amino groups of primary and secondary amines, aza rings such as N, N-dialkylpiperazines Compounds, various N, N ′, N ″ -triacylaminoaminoalkylhexahydrotriazines, β of JP-B-52-43517
-Aminocarbonyl catalyst, β-aminonitrile catalyst of JP-B-53-14279, etc., organometallic urethane-forming catalyst (tin acetate, tin octylate, tin oleate, tin laurate, dibutyltin diacetate, dibutyltin dilaurate, Dibutyltin dichloride, lead octanoate, lead naphthenate, nickel naphthenate, cobalt naphthenate, etc.) and the like. These catalysts are used alone or as a mixture, and the amount used is 0.0001 to 10.0 parts based on 100 parts of the compound having active hydrogen.

The blowing agent in the present invention, water, trichloromonofluoromethane (F-11), dichlorodifluoromitane, methylene chloride, trichlorotrifluoroethane, dibromotetrafluoroethane, trichloroethane, pentane,
One or a mixture of two or more such as n-hexane.

The foam stabilizer in the present invention is a conventionally known organic silicon surfactant, for example, L-520, L-53 manufactured by Nippon Unicar Co., Ltd.
2, L-540, L-544, L-550, L-3550, L-5305, L-3600, L-
3601, L-5305, L-5307, L-5309, L-5710, L-5720, L-57
40M, L-6202, etc., SH- from Torre Silicone
190, SH-192, SH-194, SH-200, SRX-253, SRX-274C, SF
-2961, SF-2962, SRX-280A, SRX-294A, etc., Shin-Etsu Silicone F-114, F-121, F-122, F-220, F-23
0, F-258, F-260B, F-317, F-341, F-601, F-606, X-20
-200, X-20-201, etc., TF manufactured by Toshiba Silicone Co., Ltd.
A-4200, TFA-4202, B-4113 made by Goldschmidt
And so on.

The amount of these foam stabilizers used is 0.1 to 5 parts by weight based on 100 parts by weight of the total amount of the compound having active hydrogen and polyisocyanate.

In the present invention, in addition to the above, if necessary, a stabilizer, a filler,
Colorants and the like can be used.

To carry out the present invention, a predetermined amount of a polyol, a crosslinking agent, a foam stabilizer, a catalyst, a foaming agent and other auxiliaries are mixed to obtain a resin component. Further, polyisocyanate is mixed to obtain a polyisocyanate component.

On the other hand, a slab foam having a predetermined size is cut out from a polyurethane elastic foam slab having a predetermined hardness and placed at a predetermined position in a mold.

Using a urethane foaming machine, the mixing ratio of both components is NCO / H =
Mix so as to be 0.70 to 1.40, pour into the space inside the mold in which the slab foam is installed, immediately close the lid and foam and cure. The mold may be preheated to 30 to 50 ° C. if necessary, and may be heated to completely cure it after the foaming is completed. After the completion of curing, the different hardness polyurethane tan foam molded product is taken out of the mold.

(Operation and Effect) When the molded product of different hardness polyurethane according to the present invention is used as a seat and a backrest of an automobile, it is possible to enhance the retention of the body of the driver and passengers of the automobile. Further, since the positions of the boundary surfaces of the foams having different hardness are constant, it is possible to eliminate the variation in the quality of the foams. Further, since the hardness of the boundary surface does not increase so much, the feeling of foreign matter is not generated in the foam and the user does not feel uncomfortable.

(Example) Next, the Example of this invention is described. The following raw materials were used for the Example.

Polyol A: Using glycerin as an initiator, 83.8 mol of propylene oxide is addition-polymerized, and then ethylene oxide is added to 15.8
Hydroxyl number 34 mg KOH / g obtained by molar addition polymerization, 1st
Polyether polyol having a content of primary hydroxyl groups of 71% by weight.

Polyol B ... Acrylonitrile 8 in Polyol A
Weight% hydroxyl value obtained by graft polymerization 32 mg KOH / g
Polymer polyol of.

Catalyst C: 33% diethylene glycol solution of triethylenediamine.

Catalyst D: Bis (dimethylaminoethyl) ether.

Catalyst E ... N-propylmorpholine.

Silicone oil F …… Nippon Unicar's foam stabilizer L-5309 Isocyanate G …… with crude MDI with NCO group content of 31% by weight
Equal amount mixture with carbodiimide-modified MDI with NCO group content 28% by weight Isocyanate H ... 80 / 20-TDI with NCO group content 48.3% by weight
And a mixture of crude MDI having an NCO group content of 31% by weight in a 4: 1 weight ratio. The foam physical properties were measured according to JIS K-6301 and -6401.

Hardness was measured by 25% indentation hardness (ILD), and sag factor was expressed as the ratio of 65% indentation hardness to 25% indentation hardness.

The compounding amounts in Tables 1 and 2 are shown in parts by weight.

Examples 1 to 4 Polyol A, water, catalysts C and D, silicone oil F, diethanolamine, and F-11 were mixed in the amounts shown in Table 1 to prepare resin solutions. This resin solution was mixed with 52.7 parts of isocyanate G, and the mixture was poured into a mold having a thickness of 100 mm and foamed to obtain a molding foam. The hardness of this forming foam 32 was 20 kg / 314 cm ² .

Separately, a slab foam having a thickness of 20 mm was cut out from a slab of an elastic foam having a hardness of 11.3 kg / 314 cm ² .

Place a slab foam on the bottom of a 350 x 350 x 100 mm aluminum test mold, inject the above mixture of range component and isocyanate G on it, and close the lid and cure at room temperature to release it and mold it with different hardness polyurethane foam. A molded product was obtained. The reactivity at the time of free foaming in this formulation was a cream time of 3 to 6 seconds and a rise time of 35 to 66 seconds.

The obtained different hardness polyurethane foam molded product has a slab foam and the depth of the reaction mixture liquid impregnated into the slab foam on the boundary surface between the molding slab and the slab part and above it. The foamed and hardened urethane foam part was completely bonded. The moldability and foam feel of the obtained urethane foam molding were very good because the degree of impregnation of the urethane reaction mixture into the slab was small.

Example 5 Polyol B, water, catalysts C, D, E, silicone oil F,
A resin solution is prepared by mixing diethanolamine in the weight ratio shown in Table 1. To 536 g of this resin solution, 197 g of isocyanate H was added, and after stirring for 6 seconds, this reaction mixture solution was poured into a 350 x 350 x 100 mm aluminum test mold, the lid was closed, and the mixture was cured at room temperature and then demolded. A urethane foam molded product was obtained. The reactivity during free foaming in this formulation was a cream time of 3 to 4 seconds and a rise time of 45 seconds, and the hardness was 21 kg / 314 cm ² .

Next, the slab foam of Example 1 was placed on the bottom surface of this mold, and the above raw material mixture was injected. The obtained urethane foam molded products of different hardness had a good feel of foam, like the urethane foam molded products obtained in Examples 1 to 4.

Comparative Example 1 A urethane foam molded product was obtained in the same manner as in Example 1 except that the catalyst C was reduced in Example 4 and the formulation shown in Comparative Example 1 in Table 1 was used. The reactivity at the time of free foaming in this formulation was a cream time of 6 to 7 seconds and a rise time of 85 seconds.

This urethane foam molded product had different hardness between the slab part and the molded urethane foam part that was foamed and hardened on it, but the depth of impregnation of the reaction mixture into the slab foam on the boundary surface was It was as large as 5 mm, and the foam feeling of the obtained urethane foam molding was poor.

Comparative Examples 2 and 3 A urethane foam molded product was obtained in the same manner as in Example 1 except that the catalyst amount was reduced in Example 5 and the formulations shown in Comparative Examples 2 and 3 shown in Table 1 were used. . The reactivity during free foaming in this formulation is cream time 4-7 seconds,
The rise time was 65 to 98 seconds.

This urethane foam molded product had different hardness between the slab part and the molded urethane foam part foam-cured thereon, but the depth of the impregnation of the reaction mixture into the slab foam was 5 at the boundary surface. The foam feeling of the urethane foam molded product obtained as large as ~ 6 mm was poor.

Examples 6-11 To 110.9 parts of resin premix having the composition described in Example 3 in Table 1, 47.4 parts of isocyanate G or 52.7 parts of isocyanate G are mixed.
The parts were mixed and stirred for 6 seconds, and various amounts of the reaction mixture were poured into an aluminum mold having a thickness of 20 mm and a slab foam of Example 1 placed on the bottom surface and having a thickness of 100 mm. After curing, the mold was removed to obtain a urethane foam molded article of different hardness. The reactivity in this formulation was a cream time of 5 to 6 seconds and a rise time of 48 to 53 seconds. The physical properties of the foam are shown in Table 2.

In this different hardness urethane foam molded product, the depth of impregnation of the reaction mixture into the slab foam is independent of the injection amount, and the ratio of the resin component and the isocyanate, and in any case, as small as 1 to 3 mm, The foam feel is good and the sag factor is 3.3 to 3.5 compared to the foams of Comparative Examples 5 and 6.
And increased significantly.

Comparative Example 5 40.9 parts of Isocyanate G was mixed with 110.9 parts of the resin solution having the composition described in Example 3 in Table 1 and treated in the same manner as in Example 9 to obtain a urethane foam molded product. The sag factor of this urethane foam was 2.92.

Comparative Example 6 The slab foam used in Example 1 was 350 × 350 × 100 mm.
It was cut into pieces and the hardness was measured. The sag factor for this form was 2.22.

[Brief description of drawings]

FIG. 1, FIG. 2 and FIG. 3 show cross sections of a seat for a seat with a bank of different hardness polyurethane foam. FIG. 4 shows a cross section of the headrest. In FIGS. 1 to 4, reference numerals 1, 21, 31, 41 denote slab foams, and 2, 22, 32, 42 denote molding foams. Also 3, 2
3, 33 and 43 indicate boundaries.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area B29L 31:58

Claims (2)

[Claims] 1. A polyurethane foam comprising parts having different hardnesses, wherein parts 1, 21, 31, 41 are slab foams having a specific hardness which have already been foamed and cured, and the remaining parts 2, 22, 32. , 42 is a molding foam having a different hardness formed by injecting a raw material mixture of polyurethane foam and foam-molding integrally with the slab foam. The hardness due to impregnation at the boundary surfaces 3, 23, 33, 43 between the slab foam and the molding foam. A molded article of different hardness polyurethane foam characterized in that the thickness of the rising portion is 1 to 3 mm. 2. A polyurethane foam comprising parts having different hardnesses, wherein parts 1, 21, 31, 41 are slab foams having a specific hardness which has already been foamed and cured, and the remaining parts 2, 22, 32. , 42 has cream time 3
A molding foam having different hardness, which is formed by injecting a polyurethane foam raw material mixture having a rise time of 20 seconds to 70 seconds and being foam-molded integrally with the slab foam. The boundary between the slab foam and the molding foam is Faces 3, 23,
The thickness of the hardness increasing part due to impregnation in 33 and 43 is 1 to 3 m
A method for producing a molded product of different hardness polyurethane foam, characterized in that it is m.