JP7550097B2 - Manufacturing method of flexible polyurethane foam and flexible polyurethane foam - Google Patents

Description

The present invention relates to a method for producing flexible polyurethane foam and to flexible polyurethane foam.

Soft polyurethane foam is used in bedding such as mattresses and cleaning tools such as cleaning sponges (Patent Documents 1 and 2).

JP 2011-184502 A Patent No. 4765115

However, because flexible polyurethane foam has a fine cell structure, moisture during washing remains inside the flexible polyurethane foam and is difficult to remove, making drying time consuming.
In particular, large items such as mattresses have the problem that they take a long time to dry because the mattresses contain a large amount of moisture when washed.

The present invention has been made in consideration of the above points, and aims to provide a method for producing a flexible polyurethane foam that has excellent washing and drying properties, and a flexible polyurethane foam.

The first means is a method for producing a flexible polyurethane foam by foaming a flexible polyurethane foam raw material to obtain a flexible polyurethane foam, characterized in that the flexible polyurethane foam raw material contains a polyol, a polyisocyanate, a blowing agent, a catalyst, a foam stabilizer and a cyclic siloxane, and the flexible polyurethane foam has a drying rate of 75% or more of a measured sample after drying for 8 hours in the following washing and drying test.
In the washing and drying test, 10 ml of water is poured onto one side of a measurement sample measuring 5 x 5 x 5 cm, the measurement sample after the water pouring is dried in a thermostatic chamber at 70°C, and the weight of the measurement sample during drying is measured.
The drying rate (%) was calculated by the following formula, taking the weight difference between the measured sample after pouring water and before drying and the measured sample during drying as the weight of water remaining in the measured sample.
Drying rate (%) = (1-n/m) x 100
m: weight of poured water (g)
n: weight of water remaining in the measurement sample (g)

The second method is characterized in that the drying time required for the drying rate to reach 100% in the washing and drying test is within 15 hours in the flexible polyurethane foam obtained from the flexible polyurethane foam raw material.

According to this invention, it is possible to produce a flexible polyurethane foam with excellent washing and drying properties, and obtain a flexible polyurethane foam with excellent washing and drying properties suitable for mattresses.

1 is a table showing the configurations, physical properties, and drying properties of examples of the present invention and comparative examples.

An embodiment of the present invention will be described below.
The flexible polyurethane foam of the present invention can be obtained by foaming a flexible polyurethane foam raw material.
The flexible polyurethane foam raw materials include a polyol, a polyisocyanate, a blowing agent, a catalyst, a foam stabilizer, and a cyclic siloxane.

As the polyol, a polyether polyol or a polyester polyol is used, and a polyester polyol is more preferable.
Examples of the polyether polyol include compounds obtained by addition polymerization of an alkylene oxide to a polyhydric alcohol, as well as polypropylene glycol, polytetramethylene glycol, etc. Examples of the polyhydric alcohol include glycerin, dipropylene glycol, trimethylolpropane, etc. Examples of the alkylene oxide include ethylene oxide, propylene oxide, etc.

Examples of polyether polyols include triols obtained by addition polymerization of propylene oxide to glycerin, triols obtained by addition polymerization of ethylene oxide to the triols, and diols obtained by addition polymerization of propylene oxide to dipropylene glycol.

The polyether polyol may be a polyether ester polyol obtained by reacting a polyoxyalkylene polyol with a polycarboxylic acid anhydride and a compound having a cyclic ether group. Examples of the polyoxyalkylene polyol include polyethylene glycol, polypropylene glycol, and a propylene oxide adduct of glycerin. Examples of the polycarboxylic acid anhydride include anhydrides of succinic acid, adipic acid, and phthalic acid. Examples of the compound (alkylene oxide) having a cyclic ether group include ethylene oxide and propylene oxide. Compared to polyester polyols, polyether polyols are preferred because they have superior reactivity with polyisocyanates and do not undergo hydrolysis.

Polyester polyols that can be used include condensation polyester polyols obtained by reacting polycarboxylic acids such as adipic acid and phthalic acid with polyols such as ethylene glycol, propylene glycol, and glycerin, as well as lactone polyester polyols and polycarbonate polyester polyols.

The molecular weight of the polyol is preferably 1000-6000, the number of functional groups is 2-4, the hydroxyl value is 30-300 mgKOH/g, and the EO ratio is preferably 50% or less, more preferably 0-20%. The EO ratio is the content of ethylene oxide units when the total amount of alkylene oxide units is taken as 100% by mass. If a polyol with a high EO ratio is used, the number of cells in the flexible polyurethane foam increases, making it difficult for moisture that has penetrated into the foam to be discharged to the outside, and the washing and drying properties become poor.

As the polyisocyanate, aliphatic or aromatic polyisocyanates having two or more isocyanate groups, mixtures thereof, and modified polyisocyanates obtained by modifying them can be used. For example, tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), polymethylene polyphenyl polyisocyanate, hydrogenated MDI, 1,5-naphthalene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, tetramethylxylylene diisocyanate (TMXDI), 1,3,6-hexamethylene triisocyanate, 1,6,11-undecane triisocyanate, bicycloheptane triisocyanate, and modified products and derivatives thereof can be mentioned. In addition, other prepolymers can also be used. The polyisocyanate may be used alone or in combination of two or more. Tolylene diisocyanate (TDI) is a particularly preferred polyisocyanate.

The isocyanate index (INDEX) is preferably 80 to 120. If the isocyanate index is less than 80, it becomes difficult to obtain a flexible polyurethane foam with good mechanical properties such as tensile strength and elongation, while if it exceeds 120, the flexibility of the flexible polyurethane foam decreases. The isocyanate index is the value obtained by multiplying the number of moles of isocyanate groups per mole of active hydrogen groups contained in the urethane raw material by 100, and is calculated as [(isocyanate equivalent in flexible polyurethane foam composition/active hydrogen equivalent in flexible polyurethane foam composition) x 100].

As the blowing agent, water, alternative fluorocarbons, or hydrocarbons such as pentane can be used alone or in combination. In the case of water, carbon dioxide gas is generated during the reaction of polyol with polyisocyanate, and the foaming is caused by the carbon dioxide gas. The amount of water used as the blowing agent is preferably about 2 to 6 parts by weight, more preferably 3 to 5 parts by weight, per 100 parts by weight of polyol. When other blowing agents are used in combination with water, the amount of the other blowing agents is determined appropriately.

Catalysts include amine catalysts for polyurethane foams, and metal catalysts, which are used alone or in combination. Examples of amine catalysts include monoamine compounds, diamine compounds, triamine compounds, polyamine compounds, cyclic amine compounds, alcohol amine compounds, ether amine compounds, etc., and these may be used alone or in combination of two or more. Examples of metal catalysts include organotin compounds, organoferric compounds, organobismuth compounds, organolead compounds, organozinc compounds, etc., and these may be used alone or in combination of two or more. The amount of catalyst is determined appropriately, but an example is about 0.1 to 1.0 part by weight per 100 parts by weight of polyol.

Examples of foam stabilizers include silicone compounds, anionic surfactants such as sodium dodecylbenzenesulfonate and sodium laurate, polyether siloxanes, and phenolic compounds. The amount of foam stabilizer is about 0.1 to 5.0 parts by weight per 100 parts by weight of polyol.

Examples of cyclic siloxanes include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane, and in particular, cyclic siloxanes (n=3 to 6) represented by the following formula (A) are preferred. The amount of cyclic siloxane is preferably 0.3 to 3 parts by weight per 100 parts by weight of polyol. By blending 0.3 to 3 parts by weight of cyclic siloxane, the flexible polyurethane foam can be made to have a small cell count and high breathability.

The flexible polyurethane foam raw material may contain known additives such as a crosslinking agent, a filler, a stabilizer, a colorant, an antibacterial agent, etc., if necessary.
Examples of the crosslinking agent include glycerin, an oxide adduct of ethylenediamine, and polyfunctional alcohols.
The preferred foaming method for the flexible polyurethane foam raw materials is slab foaming. Slab foaming is a method in which polyurethane foam raw materials are mixed and discharged onto a belt conveyer, and foamed at atmospheric pressure and room temperature. The flexible polyurethane foam obtained by slab foaming is then cut to a predetermined size and used as a mattress, etc.

The air permeability (JIS K6400-7B method (Fragile type)) of the flexible polyurethane foam is preferably 120 cc/cm ² /s or more, more preferably 150 to 600 cc/cm ² /s, and further preferably 200 to 600 cc/cm ² /s.

The number of cells in the flexible polyurethane foam (JIS K6400-1) is preferably 48 cells/25 mm or less, more preferably 40 cells/25 mm or less, and most preferably 30 cells/25 mm or less.

The washing and drying properties of flexible polyurethane foam will now be described.
The flexible polyurethane foam preferably has a drying rate of 75% or more, more preferably 90% or more, of a measured sample after drying for 8 hours in the washing and drying test.
The flexible polyurethane foam has a drying rate of 75% or more after 8 hours of drying in the washing and drying test, and is therefore excellent in washing and drying properties and can be dried efficiently.

In addition, the drying time required for the flexible polyurethane foam to reach a drying rate of 100% in the washing and drying test is within 15 hours.
The flexible polyurethane foam has an excellent washing and drying property, and can be dried to the inside in a short time, since the drying time until the drying rate reaches 100% in the washing and drying test is within 15 hours.

Using the raw materials shown below, the flexible polyurethane foam raw materials of Comparative Examples 1 to 3 and Examples 1 to 4 were prepared with the formulations shown in Figure 1, and flexible polyurethane foams were produced by slab foaming. The obtained flexible polyurethane foams of Comparative Examples 1 to 3 and Examples 1 to 4 were not subjected to a membrane removal process to remove the cell membrane.

Polyol A: polyether polyol, molecular weight: 3000, functionality: 3, hydroxyl value: 56.1 mgKOH/g, EO%=5-10%, product name: GP-3050NS, manufactured by Sanyo Chemical Industries, Ltd. Polyol B: polymer polyol (polymer content 41%), molecular weight: 3000, functionality: 3, hydroxyl value: 32 mgKOH/g, EO%=5%, product name: EL941WF, manufactured by AGC Inc. Polyol C: polyether polyol, molecular weight: 3000, functionality: 3, hydroxyl value: 56.1 mgKOH/g, EO%=5-10%, product name: GP-3000, manufactured by Sanyo Chemical Industries, Ltd. Polyol D: polyether polyol, molecular weight 5000, number of functional groups 3, hydroxyl value 34 mgKOH/g, EO%=74%, product name: CP1421, manufactured by Dow Chemical Japan. Foaming agent: water. Catalyst A: amine-based catalyst, product name: 33LSI, manufactured by Air Products Japan. Catalyst B: tin catalyst, stannous octoate, product name: MRH110, manufactured by Johoku Chemical Industry Co., Ltd. Foam stabilizer A: silicone-based foam stabilizer, product name: SZ1136, manufactured by Dow Corning Toray. Foam stabilizer B: silicone-based foam stabilizer, product name: L595, manufactured by Momentive. Crosslinking agent: polyol consisting of a propylene oxide adduct of ethylenediamine, product name: EDP300, manufactured by ADEKA. Cyclic siloxane; n=5 in formula (A), boiling point 211° C., product name: SH-245, manufactured by Dow Corning Toray Polyisocyanate; 2,4-TDI/2,6-TDI=80/20, product name: Coronate T-80, manufactured by Nippon Polyurethane Industry Co., Ltd.

The density (JIS K7220), cell number (JIS K6400-1), air permeability (JIS K6400-7B method (Fragile type), sample thickness 10 mm), and compression set (JIS-K6400-4) were measured for the flexible polyurethane foams of each comparative example and each example.

The washing and drying test was carried out on the flexible polyurethane foams of each comparative example and each example as follows. A measurement sample of 5 x 5 x 5 cm was prepared from each flexible polyurethane foam by cutting, and the weight of the measurement sample was measured before the start of the test. 10 ml of tap water was poured from the top of the measurement sample using a syringe, and the measurement sample after the water injection was placed on a mesh shelf in a dryer (product name: Isuzu Manufacturing, SSR-115) heated to 70°C and dried. The measurement sample was then taken out of the dryer every two hours after the start of drying, the weight of the measurement sample was measured, and the drying rate was calculated using the above-mentioned drying rate formula. Drying at 70°C was continued until the drying rate reached 100%.

For each of the comparative examples and examples, the drying property of the flexible polyurethane foams was evaluated based on the measurement results and in accordance with the following criteria.
The drying property was evaluated as follows: after 8 hours of drying, a drying rate of 90 to 100% was rated as "A", 75 to less than 90% was rated as "O", and less than 75% was rated as "X".

Each example and comparative example will be described in detail below.
Comparative Example 1
Comparative Example 1 is an example that does not contain cyclic siloxane, and is composed of a formulation with an isocyanate index of 108. Comparative Example 1 has a density of 36 kg/ ^m3 , a cell count of 35 cells/25 mm, and an air permeability of 182 cc/ ^cm2 /sec, which means that the density is high and the cell count is large. Comparative Example 1 required a drying time of 16 hours to reach a drying rate of 100%, and a drying rate of 50.3% after drying for 8 hours, resulting in a drying property evaluation of "x".

Comparative Example 2
Comparative Example 2 is an example that does not contain cyclic siloxane, and is composed of a formulation in which the polyol and foam stabilizer are different from those in Comparative Example 1, does not contain a crosslinking agent, and has an isocyanate index of 102. Comparative Example 2 has a density of 28 kg/ ^m3 , a cell count of 36 cells/25 mm, and an air permeability of 79 cc/ ^cm2 /sec, with a large cell count and low air permeability. Comparative Example 2 had a drying time of 16 hours until the drying rate reached 100%, and a drying rate after 8 hours of drying of 72.9%, resulting in a drying property evaluation of "x".

Comparative Example 3
Comparative Example 3 is an example in which 95 parts by weight of polyol A with an EO rate of 5-10% and 5 parts by weight of polyol D with an EO rate of 74% are used in combination, and 0.5 parts by weight of cyclic siloxane is blended. Comparative Example 3 has a density of 25 kg/m ³ , a cell count of 50 cells/25 mm, and an air permeability of 283 cc/cm ² /sec, and has a large cell count. In Comparative Example 3, the drying time until the drying rate reached 100% was 16 hours, and the drying rate after 8 hours of drying was 66.6%, and the drying property was evaluated as "x".

Example 1
Example 1 is an example in which 100 parts by weight of polyol A with an EO ratio of 5-10% was blended with 0.3 parts by weight of cyclic siloxane. Example 1 has a density of 25 kg/m ³ , a cell count of 46 cells/25 mm, and an air permeability of 204 cc/cm ² /sec. In Example 1, the drying time until the drying rate reached 100% was 10 hours, and the drying rate after 8 hours of drying was 99.4%, resulting in a drying property evaluation of "◎".

Example 2
Example 2 is an example in which the amount of cyclic siloxane in Example 1 is increased to 0.5 parts by weight. Example 2 differs from Comparative Example 3, which contains 5 parts by weight of polyol D with an EO ratio of 74%, in that Example 2 does not contain polyol D. Example 2 has a density of 22 kg/m ³ , a cell count of 19 cells/25 mm, and an air permeability of 329 cc/cm ² /sec, with a small cell count and high air permeability. In Example 2, the drying time until the drying rate reached 100% was 8 hours, and the drying property evaluation was "◎".

Example 3
Example 3 is an example in which 70 parts by weight of polyol A with an EO rate of 5-10%, 30 parts by weight of polyol B with an EO rate of 5%, and 0.5 parts by weight of cyclic siloxane are used. Example 3 has a density of 23 kg/m ³ , a cell count of 25 cells/25 mm, and an air permeability of 158 cc/cm ² /sec. Example 3 required a drying time of 12 hours to reach a drying rate of 100%, and a drying rate of 93.1% after 8 hours of drying, resulting in a drying property evaluation of "◎".

Example 4
Example 4 is an example in which the amount of cyclic siloxane in Example 3 was increased to 1 weight. Example 4 has a density of 23 kg/ ^m3 , a cell count of 20 cells/25 mm, and an air permeability of 214 cc/ ^cm2 /sec. Example 4 required a drying time of 12 hours to reach a drying rate of 100%, and a drying rate of 97.7% after 8 hours of drying, resulting in a drying property evaluation of "◎".

Thus, the present invention makes it possible to produce a flexible polyurethane foam having excellent washing and drying properties, and to obtain a flexible polyurethane foam having excellent washing and drying properties suitable for a mattress.
The present invention is not limited to the embodiments, and can be modified without departing from the spirit of the invention.

Claims (10)

In a method for producing a flexible polyurethane foam, a flexible polyurethane foam raw material is foamed to obtain the flexible polyurethane foam,
The flexible polyurethane foam raw material contains a polyol, a polyisocyanate, a blowing agent, a catalyst, a foam stabilizer, and a cyclic siloxane,
The polyol comprises a polyether polyol,
The polyether polyol contains only those having an ethylene oxide unit content of 20% or less when the total amount of alkylene oxide units is taken as 100% by mass,
The flexible polyurethane foam is characterized in that a dryness rate of a measured sample after drying for 8 hours in the following washing and drying test is 75% or more.
In the washing and drying test, 10 ml of water is poured onto one side of a measurement sample measuring 5 x 5 x 5 cm, the measurement sample after the water pouring is dried in a thermostatic chamber at 70°C, and the weight of the measurement sample during drying is measured.
The drying rate (%) was calculated by the following formula, taking the weight difference between the measured sample after pouring water and before drying and the measured sample during drying as the weight of water remaining in the measured sample.
Drying rate (%) = (1-n/m) x 100
m: weight of poured water (g)
n: weight of water remaining in the measurement sample (g) The method for producing flexible polyurethane foam according to claim 1, characterized in that the drying rate of the measurement sample after drying for 8 hours is 90% or more. 3. The method for producing a flexible polyurethane foam according to claim 1, wherein the flexible polyurethane foam has an air permeability of 120 cc/cm ² /sec or more as measured based on JIS K6400-7B method. The method for producing a flexible polyurethane foam according to any one of claims 1 to 3, characterized in that the number of cells of the flexible polyurethane foam measured based on JIS K6400-1 is 48 cells/25 mm or less. In a flexible polyurethane foam obtained from a flexible polyurethane foam raw material,
The flexible polyurethane foam raw material contains a polyol,
The polyol comprises a polyether polyol,
The polyether polyol contains only those having an ethylene oxide unit content of 20% or less when the total amount of alkylene oxide units is taken as 100% by mass,
A flexible polyurethane foam characterized in that the drying time required for the drying rate to reach 100% in the following washing and drying test is within 15 hours.
In the washing and drying test, 10 ml of water is poured onto one side of a measurement sample measuring 5 x 5 x 5 cm, the measurement sample after the water pouring is dried in a thermostatic chamber at 70°C, and the weight of the measurement sample during drying is measured.
The drying rate (%) was calculated by the following formula, taking the weight difference between the measured sample after pouring water and before drying and the measured sample during drying as the weight of water remaining in the measured sample.
Drying rate (%) = (1-n/m) x 100
m: weight of poured water (g)
n: weight of water remaining in the measurement sample (g)
The flexible polyurethane foam according to claim 5, characterized in that the drying rate of the measured sample after drying for 8 hours in the washing and drying test is 75% or more. 7. The flexible polyurethane foam according to claim 5, wherein the air permeability measured in accordance with JIS K6400-7B is 120 cc/cm ² /sec or more. The flexible polyurethane foam according to any one of claims 5 to 7, characterized in that the number of cells measured according to JIS K6400-1 is 48 cells/25 mm or less. The flexible polyurethane foam according to any one of claims 5 to 8, characterized in that the flexible polyurethane foam raw material contains a cyclic siloxane. 10. The flexible polyurethane foam according to claim 5, which is for use in a mattress.

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