JP4916765B2 - Polyol composition for open cell flexible polyurethane foam and method for producing open cell flexible polyurethane foam - Google Patents

Description

  The present invention relates to a polyol composition for molded open-cell flexible polyurethane foam that exhibits a predetermined rebound resilience without crushing, and a method for producing a molded open-cell flexible polyurethane foam that exhibits a predetermined rebound resilience without crushing. It is.

  A flexible polyurethane foam using a polyisocyanate compound containing a prepolymer is known as a flexible polyurethane foam having good productivity, high rebound resilience and excellent mechanical strength (Patent Documents 1, 2, etc.). ).

  Patent Documents 1 and 2 use a polyisocyanate compound containing a prepolymer obtained by reacting a polyisocyanate compound with a polyol compound, both of which are molded polyurethane soft polyurethanes using a polymer polyol as a suitable polyol compound. A form is disclosed.

JP-A-6-228259 JP 2004-115820 A

  Molded (mold) flexible polyurethane foam is essentially an open-cell foam because the volatilization of foaming gas is suppressed by the mold and the urethane foam skin layer formed on the mold surface. is there. In particular, the flexible polyurethane foam disclosed in Patent Documents 1 and 2 and the like uses a polymer polyol as an essential component of a polyol compound, so that it has good productivity and high rebound elastic modulus and excellent mechanical properties. Although it has strength, it is a closed-cell foam immediately after production, and in order to exert a predetermined rebound resilience, the crushing process that breaks the cell membrane that forms the closed-cell to form an open-cell foam Is essential. For such crushing, a device such as a compression roll is required, and it is difficult to sufficiently respond to a request for cost reduction. In particular, a large molded product such as a mattress cushion material requires a large crushing apparatus, and more expensive equipment is required.

  In view of the above-mentioned problems of the known technology, the present invention is a molded open-cell flexible polyurethane foam that has good productivity, high resilience, excellent mechanical strength, and does not require a crushing process. It is an object of the present invention to provide a method for producing a polyol composition and a molded open-cell flexible polyurethane foam.

The polyol composition of the present invention contains at least a polyol compound, water as a foaming agent, a foam stabilizer and a catalyst, and reacts with a polyisocyanate compound to form a flexible polyurethane foam in a mold. A polyol composition for polyurethane foam,
The polyol composition does not contain a polymer polyol,
The polyol compound uses at least one selected from initiators having 3 or 4 functional groups as an initiator, and uses a polyether polyol having an average molecular weight of 4000 to 8000 and a bifunctional initiator and having an average molecular weight of 1000 to 4000. It contains ether glycol, and the polyether polyol / polyether glycol weight ratio is 99/1 to 90/10.

  By using the polyol composition having the above composition, an open-cell flexible polyurethane foam having good productivity, high rebound resilience, and excellent mechanical strength (tensile strength of 180 kPa or more, preferably 190 kPa or more) is obtained. It can be manufactured by molding without requiring a crushing step. The polyether polyol / polyether glycol weight ratio is more preferably 98/2 to 92/8.

  In said polyol composition, it is preferable that the said polyether polyol is an ethylene oxide polymer unit at the terminal, and the content rate of the said ethylene oxide polymer unit is 5 to 20 weight%.

  By using the polyol composition having such a configuration, an open-cell flexible polyurethane foam can be produced more reliably without the need for a crushing step.

In the above polyol composition, each of the polyether polyols comprises a polyether polyol (A) and a polyether polyol (B) having an ethylene oxide content of 5 to 20% by weight,
The average molecular weight of the polyether polyol (A) is M (A), the ethylene oxide content is E (A), the average molecular weight of the polyether polyol (B) is M (B), and the ethylene oxide content is E. When (B), (M (A) -M (B)) is preferably 1000 or more, and the difference between E (A) and E (B) is preferably 2 or more and 10 or less.

By using the polyol composition having such a structure, an open-cell flexible polyurethane foam having a wide range of hardness of 10 N / 314 cm ² or more and 1000 N / 314 cm ² or less can be arbitrarily produced. (M (A) -M (B)) is more preferably 1500 or more. The difference between E (A) and E (B) is more preferably 8 or less.

The method for producing an open-cell flexible polyurethane foam of the present invention comprises an open-cell structure in which at least a polyol compound, water as a foaming agent, a polyol composition containing a foam stabilizer and a polyisocyanate compound are reacted and foam-cured in a mold. A method for producing a flexible polyurethane foam, comprising:
The polyol composition does not contain a polymer polyol,
The polyol compound uses at least one selected from initiators having 3 or 4 functional groups as an initiator, and uses a polyether polyol having an average molecular weight of 4000 to 8000 and a bifunctional initiator and having an average molecular weight of 1000 to 4000. Containing ether glycol, the polyether polyol / polyether glycol weight ratio is 99/1 to 90/10,
The polyisocyanate compound is a prepolymer-containing polyisocyanate containing a prepolymer having a polyether glycol having an average molecular weight of 2000 to 4000 as a constituent component and having an isocyanate group concentration of 22 to 28% by weight.

  According to the manufacturing method having the above configuration, an open-cell flexible polyurethane foam having a high resilience modulus and excellent mechanical strength can be manufactured by molding without providing a crushing step with good productivity. it can. The rebound resilience of the open cell flexible polyurethane foam obtained by the production method of the present invention is preferably 40% or more.

  In said manufacturing method, it is preferable that the terminal of the said polyether polyol is an ethylene oxide polymerization unit and the content rate of the said ethylene oxide polymerization unit is 5 to 20 weight%.

  According to the manufacturing method of the structure which concerns, an open-cell flexible polyurethane foam can be manufactured more reliably, without requiring a crushing process. In the above production method, the flexible polyurethane foam can be molded in a wide temperature range where the mold temperature is 20 to 80 ° C., which is lower than the conventional temperature range.

In the above-mentioned method for producing an open-cell flexible polyurethane foam, the polyether polyol includes a polyether polyol (A) and a polyether polyol (B) each having an ethylene oxide content of 5 to 20% by weight. ,
The average molecular weight of the polyether polyol (A) is M (A), the ethylene oxide content is E (A), the average molecular weight of the polyether polyol (B) is M (B), and the ethylene oxide content is E. When (B), (M (A) -M (B)) is preferably 1000 or more, and the difference between E (A) and E (B) is preferably 2 or more and 10 or less.

By the manufacturing method having such a configuration, an open-cell flexible polyurethane foam having a wide range of hardness of 10 N / 314 cm ² or more and 1000 N / 314 cm ² or less can be arbitrarily manufactured.

The open-cell flexible polyurethane foam of the present invention uses a polyol composition containing a predetermined polyol compound, a foaming agent, a catalyst and a foam stabilizer, and mixes the polyol composition with a polyisocyanate component to react the reactive composition. And the reactive composition can be produced by a mold forming method in which the reactive composition is foam-cured in a mold (mold). The hardness can be adjusted to some extent by the addition amount of the foaming agent and the addition amount of the crosslinking agent, but can be adjusted by the pack rate (free foaming volume / mold cavity volume). In a molded flexible polyurethane foam, the foam tends to become more closed cells when the pack ratio is increased and the hardness is increased. However, according to the present invention, even when the pack ratio is increased and the hardness is 1000 N / 314 cm ² , An open-celled flexible foam can be produced without lashing. The open cell flexible polyurethane foam of the present invention has a density of 60 to 90 kg / m ³ , more preferably 65 to 85 kg / m ³ . The rebound resilience should be high, preferably 40% or more.

  The polyether polyol which is a constituent of the polyol composition of the present invention has at least one selected from initiators having 3 or 4 functional groups as an initiator, and has an average molecular weight of 4000 to 8000. It is preferable that the end of the polyether polyol is an ethylene oxide polymer unit, and the content of the ethylene oxide polymer unit is 5 to 20% by weight.

  As the initiator for the polyether polyol, a known trifunctional or tetrafunctional initiator can be used without limitation. Specific examples of trifunctional initiators include trimethylolpropane, triethylolpropane, triethanolamine, glycerin, aliphatic triols such as 1,2,6-hexanetriol, and alkanolamines such as monoethanolamine and diethanolamine. Examples of the tetrafunctional initiator include aromatic diamines such as pentaerythritol and toluenediamine. Among these, the use of a polyether polyol using a trifunctional initiator, particularly an aliphatic triol is more preferable because a foam having a good feel can be obtained. Two or more initiators may be used in combination, but it is more preferable to use a single initiator. The average number of functional groups of the polyether polyol is more preferably 3.5 or less, and still more preferably one using a trifunctional initiator.

  The polyether polyol whose terminal is an ethylene oxide polymerization unit is produced by ring-opening addition of propylene oxide to the above initiator and then ring-opening addition of ethylene oxide. The content of the ethylene oxide polymer unit in the polyether polyol is preferably 5 to 20% by weight, and if it is less than 5% by weight, the productivity is lowered and the mechanical strength of the foam is lowered. If the weight percentage is exceeded, the mechanical strength is also lowered.

  In the present invention, it is preferable to use two kinds of polyether polyols having different average molecular weights and ethylene oxide polymer unit content. The mixing ratio of the polyether polyol (A) having a large average molecular weight and the polyether polyol (B) having a small average molecular weight is preferably 30/70 to 70/30 in (A) / (B). / 60 to 60/40 is more preferable. Either of the ethylene oxide polymer units content (E (A) and E (B)) may be large, but it is preferable that the content of the ethylene oxide polymer units of the polyether polyol having a large average molecular weight is high.

  The polyether glycol added to the polyol composition has an action of effectively destroying the cell membrane. Therefore, an open-celled flexible polyurethane foam that does not require crushing can be produced more effectively. Polyether glycol is obtained by ring-opening addition of propylene oxide using glycol such as ethylene glycol, 1,4-butanediol, diethylene glycol as an initiator, and the end may be capped with ethylene oxide. It is more preferable that it is a propylene oxide homopolymer in terms of more excellent foam breaking effect.

  In the present invention, a crosslinking agent may be used in the polyol composition in addition to the polyether polyol, if necessary. As the crosslinking agent, it is preferable to use a low molecular weight polyhydric alcohol. Specifically, ethylene glycol, propylene glycol, 1,4-butanediol, trimethylolpropane, glycerin, 2-methyl-2,3,4- Butanetriol, 2-methyl-1,2,3-butanetriol, 2,3,4-pentanetriol, 2,3,4-hexanetriol, dimethylpentaglycerin, 1,2,4-butanetriol, pentanetetrol And polyhydric alcohols such as monoethanolamine, diethanolamine, triethanolamine, and alkanolamines such as N-methyldiethanolamine.

  In the present invention, a prepolymer-containing polyisocyanate containing an NCO group-terminated prepolymer and having an NCO group content of 22 to 28% by weight is used as the polyisocyanate compound. As the isocyanate compound constituting the prepolymer-containing polyisocyanate, polyisocyanate compounds known in the field of flexible polyurethane foam can be used without limitation, and specifically, toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI) (purified diphenylmethane) And diisocyanate (p-MDI) and crude MDI (c-MDI)), xylylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate. Among these, use of toluene diisocyanate or diphenylmethane diisocyanate (p-MDI, c-MDI) is preferable. Two or more isocyanate compounds may be used in combination.

  The NCO group-terminated prepolymer contained in the isocyanate compound is composed of a polyether glycol having an average molecular weight of 1000 to 4000 and the above polyisocyanate compound. The prepolymer may be produced separately and added to the polyisocyanate compound, or may be formed by adding a predetermined amount of polyether glycol to the polyisocyanate compound and reacting it.

  The polyether glycol which is a prepolymer constituent is appropriately selected from the compounds exemplified as the polyether glycol to be added to the polyol composition. The polyether glycol (D1; average molecular weight M (D1)) added to the polyol composition and the polyether glycol (D2; average molecular weight M (D2)) constituting the prepolymer may be the same, but M (D2 )> M (D1) is more preferable.

  As a catalyst, a well-known catalyst can be used without limitation. In particular, the use of a tertiary amine catalyst is preferable. Triethylenediamine (DABCO, TEDA 33LV, etc.), Toyocat-ET (Tosoh), bis (2-dimethylaminoethyl) ether (Niax A-1), N, N-dimethylethanol Amine (DMEA), M, N-dimethylcyclohexylamine (Polycat 8), M, N, N-tris (3-dimethylaminopropyl) amine (Polycat 9), N-methyldicyclohexylamine (Polycat 12) (Sanapro) Etc. are exemplified.

  As the foam stabilizer, known foam stabilizers can be used without limitation in the production of open-cell flexible polyurethane foam. Specifically, SF2965, SF2962, SF2904, SF2908, SRX294A, L-5366, L-5309 ( Use of commercial products such as Toray Dow Corning Silicon) and B8680 (Gold Schmidt) is preferred.

  In the manufacturing method of the flexible polyurethane foam of this invention, it is preferable that the cream time of the reactive composition which mixed the polyol composition and the polyisocyanate compound containing a prepolymer is 7 to 12 seconds.

<Raw materials>
1) Polyether polyol (A)
(A1) Polyether polyol average molecular weight (terminal group determination method) (M (A)) 7000 in which ethylene oxide was added after ring-opening addition of propylene oxide using glycerol as an initiator
Ethylene oxide unit content 14% by weight
(A2) Polyether polyol average molecular weight (end group determination method) 6000 after addition of ethylene oxide after ring-opening addition of propylene oxide using glycerol as an initiator
Ethylene oxide unit content (E (A)) 14% by weight
2) Polyether polyol (B)
(B1) Polyether polyol average molecular weight (end group determination method) 4000 in which ethylene oxide was added after ring-opening addition of propylene oxide using glycerol as an initiator
Ethylene oxide unit content (E (B)) 9% by weight)
(B2) Polyether polyol average molecular weight (end group determination method) 4500 in which ethylene oxide was added after ring-opening addition of propylene oxide using glycerol as an initiator
Ethylene oxide unit content (E (B)) 7% by weight)
3) Polyether glycol, commercially available bifunctional polypropylene glycol having an average molecular weight of 2000 4) Crude MDI having an NCO group concentration of 26% by weight by adding and reacting bifunctional prepolymer-containing polyisocyanate compound and polypropylene glycol having an average molecular weight of 3000 Sprasec 201; ICI)
The raw materials other than the above are listed in Table 1.

(Examples 1-4)
Molding of open cell flexible polyurethane foam was carried out according to the formulation shown in Table 1. In the formulations of Examples 1 and 2, [M (A) -M (B)] is 3000, and the difference between E (A) and E (B) is 5% by weight. In the formulations of Examples 3 and 4, [M (A) -M (B)] was 1500, and the difference between E (A) and E (B) was 7% by weight. Mixing of a polyol composition and a polyisocyanate compound is 100/60 (weight ratio).

Molding was performed at a molding temperature of 60 ° C. using an aluminum mold having a cavity of 300 mm length, 300 mm width, and 100 mm depth. About Example 1, although shape | molding was performed at 30 degreeC and 75 degreeC, the same flexible foam was obtained at any temperature. Further, in Example 1, when the foam was added to reduce the foaming agent addition amount to increase the density and the hardness was about 500 N / 314 cm ² and about 700 N / 314 cm ² , it was open-celled without crushing. .

<Evaluation>
1) Density A sample having a length of 100 mm, a width of 100 mm, and a thickness of 50 mm was cut out from the produced open-cell flexible polyurethane foam, and the weight was measured and calculated.

2) Hardness The method for measuring the hardness is as follows.
a) Test piece: One piece of 50 × 380 × 380 (mm) is taken from the slab foam.
b) Testing machine: The test piece can be compressed between a pressure plate moving at a constant speed of 100 ± 20 mm per minute in the vertical direction and a fixed support plate. The load is accurate to ± 1% or ± 1 N or more under load. Use a specimen that can measure the thickness of the specimen with an accuracy of ± 0.25 mm.
-Support plate: Unless otherwise specified, it shall have a hard surface that is larger, horizontal and smooth than the specimen. In addition, in order to allow air to escape from under the test piece, it has a diameter of about 6 mm and vent holes of about 20 mm.
・ Pressure plate: A ball joint is attached to move freely by vertical movement.
A flat disk with a diameter of 200 ⁺³ ₋₀ mm and a lower edge with a radius of 1.0 ⁺⁵ ₋₀ mm.
The lower surface of the pressure plate must be a smooth surface that has not been polished.
c) Measuring method: Place the test piece flat on the center of the tester table, place the pressure plate on the upper surface of the test piece, and read the thickness up to 0.1 mm when the load is 5 ⁺⁰ _-2 N. This is the initial thickness.
Next, press the pressure plate at 25 ± 1% of the original thickness at a speed of 100 ± 20 mm per minute, read the load when 20 seconds have passed after the stationary to 1N, hardness, (H) is the read load To do.
The measurement is performed once, and the hardness is rounded according to JIS-Z-8401.

3) Rebound resilience It was measured in accordance with JIS K 6400.

  The results of evaluation are shown in the lower part of Table 1. The obtained flexible polyurethane foam was open-celled without crushing, had a rebound elastic modulus superior to that of a general flexible polyurethane foam, and was excellent in touch. The strength was also better than that of general flexible polyurethane foam.

Claims (3)

A method for producing an open-cell flexible polyurethane foam in which at least a polyol compound, water as a foaming agent, a polyol composition containing a foam stabilizer and a polyisocyanate compound are reacted and foam-cured in a mold,
The polyol composition does not contain a polymer polyol,
The polyol compound uses at least one selected from initiators having 3 or 4 functional groups as an initiator, and uses a polyether polyol having an average molecular weight of 4000 to 8000 and a bifunctional initiator and having an average molecular weight of 1000 to 4000. Containing ether glycol, the polyether polyol / polyether glycol weight ratio is 99/1 to 90/10,
The polyisocyanate compound includes a prepolymer having a polyether glycol having an average molecular weight of 2000 to 4000 as a constituent component, and is a prepolymer-containing polyisocyanate having an isocyanate group concentration of 22 to 28% by weight. A method for producing polyurethane foam. The method for producing an open-cell flexible polyurethane foam according to claim 1 , wherein the polyether polyol has an ethylene oxide polymer unit at a terminal and a content of the ethylene oxide polymer unit is 5 to 20% by weight. . Each of the polyether polyols comprises a polyether polyol (A) and a polyether polyol (B) having an ethylene oxide content of 5 to 20% by weight,
The average molecular weight of the polyether polyol (A) is M (A), the ethylene oxide content is E (A), the average molecular weight of the polyether polyol (B) is M (B), and the ethylene oxide content is E. when the (B) (M (a) -M (B)) is 1000 or more, according to claim 1 or 2 difference E (a) and E (B) is equal to or is 2 to 10 A process for producing an open-cell flexible polyurethane foam as described in 1).