JP2012046668A - Polyurethane foam for mattresses, and mattress comprised of the polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyurethane foam and a mattress that are manufactured simply, environment-friendly, and furthermore provide a user with a comfortable bed.SOLUTION: The polyurethane foam for a mattress is obtained by performing foaming and reaction of a raw material consisting of a polyol component, polyisocyanate component, and a foaming agent, wherein the polyol component comprises castor oil (a1) and a polyol (a2), that is a polyether polyol whose average functional group number is 2.5-4.5 and hydroxyl value is 40-60 mgKOH/g and/or a polymer polyol whose average functional group number is 2.5-4.0 and hydroxyl value is 25-50 mgKOH/g, and a content of the caster oil (a1) against the total polyol components is 25-75 wt.% and that of the polyol (a2) against the total polyol components is 25-75 wt.%, and the mattress comprises the polyurethane foam.

Description

  The present invention relates to a polyurethane foam, particularly a polyurethane foam for a mattress, and a mattress using the polyurethane foam.

  Conventionally, what was manufactured using the polyurethane foam as a mattress for bedding is known. The mattress for bedding is required to have a feeling of fit that wraps a portion of a person sleeping and sinking with an appropriate force as a sleeping comfort. As a mattress for bedding using polyurethane foam, from the viewpoint of such a sleeping comfort, a laminated mattress composed of two or more polyurethane foam layers having different hardness or / and elasticity has been proposed (Patent Documents 1 and 2). .

  However, the laminated mattress as described above has a multilayer structure, and the layers are bonded together with an adhesive, so that the production is complicated. In addition, each polyurethane foam layer uses a synthetic material as a raw material and uses an adhesive, so that the environmental load is relatively large.

JP 2002-34730 A JP 2002-238708 A

  An object of the present invention is to provide a polyurethane foam and a single-layer mattress that can provide good sleeping comfort, are easy to manufacture, and are environmentally friendly.

The present invention is a polyurethane foam obtained by foaming and reacting a raw material composition containing a polyol component, a polyisocyanate component and a foaming agent, wherein the polyol component is
(A1) castor oil; and (a2) a polyether polyol having an average functional group number of 2.5 to 4.5 and a hydroxyl value of 40 to 60 mgKOH / g and / or an average functional group number of 2.5 to 4.0 and a hydroxyl value of 25 to 50 mgKOH. / G polymer polyol;
A polyurethane foam for mattresses comprising 25 to 75% by weight of castor oil (a1) and 25 to 75% by weight of polyol (a2) based on the total polyol component, and polyurethane It relates to a mattress made of foam.

  The polyurethane foam of the present invention is easy to manufacture, is environmentally friendly, and can provide good sleeping comfort.

  The polyurethane foam of the present invention is obtained by foaming and reacting a raw material composition containing a polyol component, a polyisocyanate component and a foaming agent, and optionally a catalyst and a foam stabilizer.

<Polyol component>
The polyol component contains at least castor oil (a1) and polyol (a2).

  Castor oil (a1) is an ester of fatty acid and glycerin, and is a vegetable oil in which about 90% of the fatty acid is ricinoleic acid. Since ricinoleic acid is an unsaturated fatty acid having a hydroxyl group, castor oil is a polyester polyol which can have a hydroxyl value of 150 to 170 mg KOH / g, particularly around 160 mg KOH / g in an unmodified state.

  As the castor oil (a1), refined castor oil, semi-refined castor oil, unrefined castor oil or the like may be used, but it is preferable to use purified castor oil. Moreover, what passed through the deodorizing process is more preferable. Polyols having a castor oil modified and having a hydroxyl value of less than 100 mg KOH /, for example, about 30 to 70 mg KOH / g are also found, but the sleeping comfort is deteriorated due to the push-up feeling, which is particularly preferable for use in a single-layer mattress. Absent. In addition, when the said castor oil is used, since the modification | denaturation process which uses energy is not required, it is environmentally preferable and manufacture of a foam becomes still simpler.

  A commercial item can be used for castor oil (a1). Specifically, H-30 which is a castor oil polyol (manufactured by Ito Oil Co., Ltd., hydroxyl value: about 160 mgKOH / g, deodorized product), LAV which is a castor oil polyol (manufactured by Toyokuni Oil Co., Ltd., hydroxyl value: about 160 mgKOH / g), etc. Is mentioned.

  The content of castor oil (a1) with respect to the total polyol component is 25 to 75% by weight, preferably 40 to 65% by weight. When the content is too large, the resilience of the polyurethane foam is lowered, and the resilience is excessively reduced, so that a feeling of bottoming occurs, and as a result, a feeling of fit cannot be obtained, resulting in poor sleeping comfort. If the content is too small, the resilience of the polyurethane foam increases and the resilience becomes excessively large, resulting in a push-up feeling, resulting in a poor fit and poor sleeping comfort. Since it is better to add more castor oil for the purpose of reducing the environmental load, the particularly preferred content is 45 to 60% by weight. Castor oil (a1) may be contained in two or more types, and in that case, the total amount thereof may be within the above range.

  The polyol (a2) is a polyether polyol (a2-1) having an average number of functional groups of 2.5 to 4.5, preferably 2.5 to 3.5 and a hydroxyl value of 40 to 60 mgKOH / g, preferably 50 to 60 mgKOH / g. And / or a polymer polyol (a2-2) having an average number of functional groups of 2.5 to 4.0, preferably 2.7 to 3.7, and a hydroxyl value of 25 to 50 mgKOH / g, preferably 30 to 45 mgKOH / g. . Thereby, a polyurethane foam having good sleeping comfort can be obtained. When the average functional group number of the polyether polyol (a2-1) is less than 2.5, the hardness becomes insufficient, and the compressive residual strain deteriorates, so-called sag increases. When it exceeds 4.5, it becomes difficult to foam the urethane foam, the productivity is lowered, and the physical properties of elongation and tensile strength are lowered. When the polyether polyol (a2-1) has a hydroxyl value of less than 40, it is difficult to obtain sufficient hardness, and the versatility of the polyol is low and expensive. When it exceeds 60, the foaming stability is poor and a good foam is obtained. It becomes difficult to obtain. When the average number of functional groups of the polymer polyol (a2-2) is less than 2.5, the hardness becomes insufficient, the compression residual strain deteriorates, and so-called sag increases. When it exceeds 4.0, it becomes difficult to foam the urethane foam, and productivity is lowered and physical properties such as elongation and tensile strength are lowered. When the hydroxyl value of the polymer polyol (a2-2) is less than 25, the viscosity becomes high and the productivity becomes low, and when it exceeds 50, the polymer content becomes low and it becomes difficult to obtain a foam having the desired hardness.

In the present specification, the average number of functional groups is an average value of the number of hydroxyl groups per molecule. In addition, the theoretical value calculated from the average number of functional groups of the raw material is regarded as the number of functional groups.
The hydroxyl value is a value measured in accordance with JIS K 1557, but it does not have to be measured in accordance with the above standard, and may be measured by any method as long as the principle and principle comply with the standard. May be.

  As the polyether polyol (a2-1), polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, sorbitol, sucrose, and propylene glycol, or the average number of functional groups is the average number of functional groups of the polyether polyol (a2-1). A compound obtained by adding an alkylene oxide such as propylene oxide and / or ethylene oxide to a polyhydric alcohol mixture mixed so as to fall within the range is used.

  The polyether polyol (a2-1) is a polyol having an average functional group number of 3, an average molecular weight of 3000, and a hydroxyl value of 56, which is obtained by adding an alkylene oxide such as propylene oxide and / or ethylene oxide to glycerin. A type of polyol is preferred.

  As the number average molecular weight, a hydroxyl value-converted molecular weight measured according to JIS K 1557 is used.

  Polyether polyol (a2-1) can be obtained as a commercial product. As a commercially available product, for example, a so-called No. 3000 type polyol (average functional group number 3, hydroxyl value 56, molecular weight 3000) can be used.

  The polymer polyol (a2-2) is obtained by finely dispersing a polymer in a polyether polyol. Examples of the polymer to be dispersed include addition polymerization polymers such as homopolymers and copolymers having vinyl monomers such as acrylonitrile, styrene, alkyl methacrylate, and alkyl acrylate as monomer components. Among them, styrene homopolymers and acrylonitrile and styrene One type or two or more types selected from these copolymers are preferred. The polyether polyol in which the polymer is dispersed is obtained by addition polymerization of an alkylene oxide to a polyhydric alcohol. As the polyhydric alcohol, glycerin, trimethylolpropane, pentaerythritol, or the like is used, and as the alkylene oxide. In this case, ethylene oxide, propylene oxide or the like is used. As such a polyether polyol, among them, a polyether polyol having a number average molecular weight of 2000 to 4000 and a hydroxyl value of about 40 to 60 obtained by adding propylene oxide and / or ethylene oxide to glycerin can be suitably used. In addition, content of the polymer in a polymer polyol (a2-2) is about 20 to 50 weight% normally.

  The polymer polyol (a2-2) can be obtained as a commercial product such as “POP-45” (manufactured by Mitsui Chemicals), “POP-3943” (manufactured by Dow Chemical).

  Content with respect to the whole polyol component of a polyol (a2) is 25 to 75 weight%. In particular, when the polyether polyol (a2-1) is used alone, its content is preferably 40 to 60% by weight. When the polymer polyol (a2-2) is used alone, the hardness may increase excessively, and therefore the content is preferably about 30 to 40% by weight. When the content of the polyol (a2) is too large, the resilience of the polyurethane foam becomes high and the resilience becomes excessively large, resulting in a feeling of pushing up, and as a result, a feeling of fit cannot be obtained, resulting in poor sleeping comfort. If the content is too small, the resilience of the polyurethane foam is lowered and the resilience is excessively reduced, resulting in a feeling of bottoming. As a result, a feeling of fit cannot be obtained, resulting in poor sleeping comfort. The polyol (a2) may contain two or more kinds of polyols, and in that case, the total amount thereof may be within the above range.

  As the polyol (a2), it is preferable to use the polyether polyol (a2-1) alone.

  The polyol component may contain other polyols in addition to the castor oil (a1) and the polyol (a2) described above. Examples of other polyols include low molecular weight polyols, dimer acid polyols, and phthalic acid polyols. Among these, a low molecular weight polyol is preferably used as a so-called cross-linking agent because the hardness of the foam can be adjusted with a small amount.

  Examples of the low molecular weight polyol include polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, trimethylolpropane, and glycerin. Preferred low molecular weight polyols are diethylene glycol and dipropylene glycol.

  The content of the other polyol with respect to the whole polyol component is 10% by weight or less, particularly 0.5 to 5% by weight, preferably 1 to 3% by weight. The other polyol may contain two or more kinds of compounds, and in that case, the total amount thereof may be within the above range.

<Polyisocyanate component>
The polyisocyanate component is a compound having two or more isocyanate groups in one molecule. As the polyisocyanate component, aromatic polyisocyanates are usually used. Specifically, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and mixtures thereof, diphenylmethane diisocyanate, polymethylene polyphenyl diisocyanate, etc. Is mentioned. Preferred are 2,4-tolylene diisocyanate and / or 2,6-tolylene diisocyanate, which are commercially available as TDI-80 and TDI-65.

  The polyisocyanate component is contained in such an amount that the NCO / OH equivalent ratio of all isocyanate groups and all hydroxyl groups in the raw material composition is 1.00 to 1.20, preferably 1.05 to 1.15. The number of all hydroxyl groups includes not only the number of hydroxyl groups in the polyol component but also the number of hydroxyl groups in water when water is used as a foaming agent described later.

<Foaming agent>
As the foaming agent, those conventionally used as a foaming agent in the field of polyurethane foam can be used. Specific examples of the foaming agent include chemical foaming agents such as water, physical foaming agents such as methylene chloride, hydrocarbons (cyclopentane, etc.), carbon dioxide gas, and liquefied carbon dioxide gas. Environmentally, it is preferable to use only water. Water functions as a chemical blowing agent by reacting with polyisocyanate to generate carbon dioxide. The amount of the foaming agent is preferably 1 to 7 parts by weight with respect to 100 parts by weight of the polyol component, and is preferably 2 to 5 parts by weight from the viewpoint of expressing a preferable density in the foam.

<Catalyst>
As the catalyst, amine-based or tin-based catalysts conventionally known in the field of polyurethane foam can be used. Examples of the amine catalyst include trimethylamine ethyl piperazine, triethylamine, tripropylamine, N-methylmorpholine, N-ethylmorpholine, triethylenediamine, tetramethylhexamethylenediamine, pentamethyldiethylenetriamine, bis (2-dimethylaminoethyl). Examples include tertiary amines such as ether, alkanolamines such as diethanolamine, dimethylaminoethoxyethanol, and dimethylethanolamine. Examples of tin-based catalysts include dibutyltin dilaurate and stannous octate. The usage-amount of a catalyst is about 0.01-8 weight part normally with respect to 100 weight part of polyol components. When two or more types of catalysts are used, the total amount thereof may be within the above range.

<Foam stabilizer>
As the foam stabilizer, silicone type such as organopolysiloxane, organopolysiloxane / polyalkylene copolymer, polyalkenylsiloxane having polyalkylene side chain, which is generally used for soft slabs and flexible molds in the field of polyurethane foam production. It is preferred to use a surfactant. The amount of the foam stabilizer used is usually about 0.2 to 6 parts by weight with respect to 100 parts by weight of the polyol component. Two or more kinds of compounds may be contained in the foam stabilizer, and in that case, the total amount thereof may be within the above range.

<Others>
The raw material composition may further contain additives such as an antioxidant, an ultraviolet absorber, a colorant, and a flame retardant.

<Method for producing polyurethane foam>
The polyurethane foam of the present invention can be obtained by sequentially reacting and foaming the raw material composition by a known production method such as a one-shot method or a molding method. In particular, when the polyurethane foam of the present invention is used for producing a mattress, the mattress is preferably produced by a one-shot method. In the one-shot method, a polyurethane foam is produced by adding each component to the mixing chamber at the same time, and mixing by vigorous stirring simultaneously with the addition of each component. The obtained polyurethane foam slab is processed into a sheet shape by being sliced to a desired thickness, and is provided for a mattress.

  In the polyurethane foam of the present invention, from the viewpoint of the environment, the proportion of the plant-derived substance in the entire raw material composition (plant degree) is preferably as large as possible, and is preferably about 30 to 50% by weight. Among the above-mentioned raw materials, the raw material included in the plant-derived substance is castor oil.

In the present specification, the value calculated by the following formula is used as the plant degree (%).
{(Total weight of plant-derived raw materials) / (Total weight of all raw materials)} × 100

<Polyurethane foam mattress>
The polyurethane foam of the present invention can be easily manufactured by using the castor oil as having a moderate resilience characteristic, and as a result, a good sleeping comfort can be obtained, and the manufacture is simple and environmentally friendly mattress, particularly A single-layer mattress can be provided. Having a moderate rebound characteristic means that the rebound characteristic is moderate, and specifically means having rebound resilience and 25% hardness, which will be described later. As a result, when the iron ball is left standing, a predetermined sinking displacement is exhibited and a good sleeping comfort is obtained.

The impact resilience of the polyurethane foam of the present invention is 15 to 30%, preferably 17 to 27%. If the resilience is too small, the resilience becomes excessively small, resulting in a feeling of bottoming. As a result, a feeling of fit cannot be obtained, resulting in poor sleeping comfort. When the resilience elasticity is too high, the resilience becomes excessively large, and a feeling of pushing up is generated.
The 25% hardness of the polyurethane foam of the present invention is 80 to 140N, preferably 80 to 130N. If the hardness is too small, the body sinks excessively, resulting in a feeling of bottoming. As a result, a feeling of fit cannot be obtained, resulting in poor sleeping comfort. If the hardness is too high, the body will not sink sufficiently and a feeling of fit cannot be obtained, resulting in poor sleeping comfort.
When an iron ball (diameter 9 cm, weight 2.9 kg) is left standing on the polyurethane foam of the present invention, the displacement of the sinking is 20 to 40 mm, particularly preferably 25 to 39 mm. When the sinking displacement is too small, the feeling of pushing up as a mattress becomes strong, and the body pressure dispersibility is lowered. If the subduction displacement is too large, the body pressure dispersibility is excellent, but a feeling of bottoming occurs, and the sleeping comfort is worsened.

  The above-mentioned physical properties of polyurethane foam are difficult to produce using conventional petroleum-based polyols, but castor oil, particularly unmodified refined castor oil having a hydroxyl value of around 160 and specific polyols. Can be used to easily obtain the above-mentioned physical properties of polyurethane foam. It is particularly important to find that the use of unmodified castor oil can further contribute to the environment.

  The polyurethane foam of the present invention can be used in the production of mattresses. The polyurethane foam of the present invention can be used as a part of an ordinary laminated mattress, but in particular, as a single-layered (urethane foam single-layer) mattress without being laminated with two or more polyurethane foams. It can be preferably used. As described above, the single-layer mattress of the present invention can be easily manufactured as a mattress without requiring an adhesion step as in the laminated type, and can further exhibit a sinking amount similar to that of the laminated type. A mattress, particularly a polyurethane foam for a mattress, usually has a thickness of 30 to 150 mm, and preferably has a sheet shape of 40 to 120 mm, more preferably 50 to 100 mm, for a single layer. The foam surface may be subjected to uneven processing such as profile processing.

  The mattress is usually obtained by accommodating a polyurethane foam for mattress in a bag made of a cloth material such as cotton or polyester, a so-called cover material. In addition, there may be a mode in which a double cover of the inner cover and the outer cover is used. For example, a mattress using the polyurethane foam of the present invention can be obtained by inserting the polyurethane foam of the present invention into a stretchable and breathable inner bag material and stuffing it into the outer bag material.

[Examples 1-7 / Comparative Examples 1-2]
A polyol-based component mixed with the components shown in Table 1 or 2 (excluding the polyisocyanate component) and the polyisocyanate component were reacted and foamed by a one-shot method to produce a long polyurethane foam slab. The slab was cut into a predetermined sheet shape.

[Evaluation]
The polyurethane foam was evaluated for the following items.
<Density>
It calculated | required based on the method of measuring the apparent density of JISK7222.

<25% hardness>
It measured based on JIS K6400-2 D method.
<Rebound resilience>
It measured based on JIS K6400-3.

<Subduction displacement>
The polyurethane foam was cut into a size of 300 × 300 × 50 mm to obtain a mat. A mat was placed on an experimental bench in an environment of 24 ° C. and 50% RH, and an iron ball having a diameter of 9 cm (2.9 kg) was left on the mat. Thereafter, the displacement of the iron ball when it was left for 1 minute was measured. The subduction displacement is the vertical length of the portion of the iron ball that has submerged in the mat. In Reference Examples 1 and 2, mats produced by the method described later were evaluated.

It can be seen that when the rebound resilience, 25% hardness, and subsidence displacement are within the above-described ranges, good sleeping comfort (feeling of fit) can be obtained.
It can be seen that when the impact resilience, 25% hardness, and sinking displacement are within the above-described preferable ranges, the sleeping comfort (feeling of fit) is further improved.

[Reference Example 1]
A commercially available high resilience type polyurethane foam (“Clara Foam 451” manufactured by Kurashiki Boseki Co., Ltd.) was used as the high resilience polyurethane foam. A commercially available low-resilience polyurethane foam (“Clara Foam 501EA” manufactured by Kurashiki Textile Co., Ltd.) was used as the low-resilience polyurethane foam. Each physical property is shown in Table 1.
A low resilience polyurethane foam (thickness 10 mm) as an upper layer was attached to a high resilience polyurethane foam (thickness 40 mm) as a lower layer using a rubber adhesive to obtain a mat having a size of 300 × 300 × 50 mm.
Table 3 shows the physical property values of the high resilience polyurethane foam and the low resilience polyurethane foam used in Reference Example 1.

[Reference Example 2]
A mat was obtained in the same manner as in Reference Example 1 except that a low-resilience polyurethane foam (thickness 20 mm) as an upper layer was attached to a high-resilience polyurethane foam (thickness 30 mm) as a lower layer.

(1) URIC H-30: A castor oil-based polyol manufactured by Ito Oil Co., Ltd., which is an unmodified castor oil refined product.
(2) Polyether polyol: A so-called # 3000 type polyether polyol obtained by adding propylene oxide to glycerin (hydroxyl value: 56, average number of functional groups: 3, number average molecular weight: 3000).
(3) Polymer polyol: Mitsui Chemicals POP-45
(4) DPG: Dipropylene glycol (hydroxyl value 836: low molecular weight polyol).
(5) TDI-80: Tolylene diisocyanate (2,4: 80%, 2,6: 20%).
(6) MR: amine catalyst manufactured by Tosoh Corporation TOYOCAT-MR (N, N, N ′, N′-tetramethyl-1,6-hexanediamine).
(7) U-28: a tin-based catalyst manufactured by Nitto Kasei Co., Ltd.
(8) L-638: Silicone foam stabilizer manufactured by Momentive Performance Materials Japan.
(9) SRX280A: silicone foam stabilizer manufactured by Toray Dow Corning.
(10) NCO / OH ratio in the entire raw material composition.
(11) The ratio of the plant-derived raw material to the whole raw material composition.

  About the polyurethane foam of the said Examples 1-7, it processed into the sheet form of 1000x2000x100mm from the manufactured polyurethane foam slab, and it inserted in the polyester cover material, and obtained the single layer type mattress. Each of the feelings of comfort was similar to that of a so-called laminated mattress and was excellent. In particular, those having a sinking amount of 25 to 39 mm had very good sleeping comfort.

Claims (7)

A polyurethane foam obtained by foaming and reacting a raw material composition containing a polyol component, a polyisocyanate component and a foaming agent,
(A1) castor oil; and (a2) a polyether polyol having an average functional group number of 2.5 to 4.5 and a hydroxyl value of 40 to 60 mgKOH / g and / or an average functional group number of 2.5 to 4.0 and a hydroxyl value of 25 to 50 mgKOH. / G polymer polyol;
A polyurethane foam for mattresses comprising 25 to 75% by weight of castor oil (a1) and 25 to 75% by weight of polyol (a2) based on the total polyol component.   The polyurethane foam for a mattress according to claim 1, wherein the polyurethane foam has a rebound resilience of 15 to 30% and a 25% hardness of 80 to 140N.   The polyurethane foam for mattresses according to claim 1 or 2, wherein a ratio (plant degree) of the plant-derived substance in the whole raw material composition is 30 to 50% by weight.   The polyisocyanate component is contained in an amount such that the NCO / OH equivalent ratio of all isocyanate groups and all hydroxyl groups in the raw material composition is 1.05 to 1.15. Polyurethane foam for mattresses.   A mattress using the polyurethane foam for a mattress according to any one of claims 1 to 4.   The mattress according to claim 5, wherein the mattress is a single-layer mattress.   The mattress according to claim 5 or 6, wherein the polyurethane foam has a thickness of 30 to 150 mm.