Polyurethane foam

Abstract

To provide a polyurethane foam having low hardness, low air permeability, and low compression set, the polyurethane foam being suitable as a sealant to be compressed between two objects.MEANS FOR SOLVING THE PROBLEM: A polyurethane foam is prepared from a polyurethane reaction composition containing a polyol component, a foam stabilizer, a catalyst, and an isocyanate component, and a gas for foaming by the mechanical froth method. The polyurethane reaction composition contains core shell rubber particles. The polyurethane foam has a 25% CLD hardness of 0.05 MPa or less in accordance with the JISK6400-2D method and a compression set of 10% or less in accordance with JISK6400-4.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to polyurethane foams having low hardness, low air permeability and low compression set. [Background technology]

[0002] Polyurethane foams obtained by the mechanical frothing method from a polyurethane reaction composition containing a polyol component, a foam stabilizer, a catalyst, and an isocyanate component, and a foam-forming gas have been proposed for use as sealing materials because they have low hardness and low breathability (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-214895 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-227392 Summary of the Invention [Problem to be solved by the invention]

[0004] However, polyurethane foams obtained by the mechanical frothing method from a polyurethane reaction composition containing a polyol component, a foam stabilizer, a catalyst, and an isocyanate component, and a foam-forming gas, are desired to have even lower compression set for use as sealing materials compressed between two objects.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to provide a polyurethane foam having low hardness, low air permeability and low compression set. [Means for solving the problem]

[0006] First Aspectis a polyurethane foam obtained by a mechanical froth method from a polyurethane reaction composition containing a polyol component, a foam stabilizer, a catalyst, and an isocyanate component, and a foam-forming gas, wherein the polyurethane reaction composition contains core-shell rubber particles, and the 25% CLD hardness according to the JIS K6400-2D method is 0.05 MPa or less, and the compression set according to JIS K6400-4 is 10% or less.

[0007] Second Aspect teeth, First Aspect The amount of the core-shell rubber particles is 0.5 to 5.0% by weight of the polyurethane reaction composition excluding the isocyanate component.

[0008] Third Aspect teeth, First or second aspect The present invention is characterized in that it is used as a sealing material. [Effects of the Invention]

[0009] According to the present invention, the polyurethane reaction composition contains core-shell rubber particles, which reduces the compression set of the polyurethane foam, thereby providing a polyurethane foam with low hardness, low breathability and low compression set that is suitable for use as a sealing material. The core-shell rubber particles are formed by coating a part or the entire surface of a particulate core component with a shell component. The particulate core component is primarily composed of a crosslinked rubbery polymer or elastomer, and the shell component is formed by graft-polymerizing a shell component polymer different from the core component onto the surface of the particulate core component, which is a known method. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a plan view of a sample for measuring breathability. [Figure 2] FIG. 2 is a cross-sectional view of the air permeability measurement chamber. [Figure 3] 1 is a table showing the formulation and evaluation of some of the examples. [Figure 4] 10 is a table showing the formulations and evaluations of other examples and comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the polyurethane foam of the present invention will be described below: The polyurethane foam of the present invention can be obtained from a polyurethane reaction composition and a foam-forming gas by a mechanical froth method.

[0012] The mechanical froth method is a method of forming polyurethane foam by feeding a mixed raw material, in which a foam-forming gas is compressed and mixed into a polyurethane reaction composition, into an O-X mixer or a nozzle with a tapered tip, and discharging it from the O-X mixer or nozzle. In the mechanical froth method, the foam-forming gas, which had been compressed until then, expands when the mixed raw material is discharged to form bubbles, and in this state, the polyol component and the isocyanate component react and harden to form polyurethane foam. Therefore, the foam-forming gas is contained within the cells of the polyurethane foam.

[0013] The polyurethane reaction composition contains a polyol component, a foam stabilizer, a catalyst, an isocyanate component, and in the present invention, further contains core-shell rubber particles. The polyol component is made of a polyol, such as a polyether polyol or a vegetable oil polyol, and two or more types of polyols may be used in combination.

[0014] Polyether polyols are characterized by their resistance to hydrolysis of polyurethane foam compared to ester polyols. Examples of polyether polyols that can be used include polyether polyols for polyurethanes, such as polyether polyols obtained by adding alkylene oxides, such as ethylene oxide and propylene oxide, to polyhydric alcohols, such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, and sucrose. The polyether polyol preferably has 2 to 4 functional groups and a molecular weight of 400 to 8,000, more preferably 2,000 to 4,000. Two or more types of polyether polyols may be used in combination.

[0015] Polyester-based polyols include polycaprolactone-based polyols and polycarbonate-based polyols, which have relatively excellent hydrolysis resistance, and preferably have a molecular weight of 500 to 2000. Polycarbonate-based polyols are particularly excellent in hydrolysis resistance. Examples of polycarbonate-based polyols include those obtained by dealcoholization reaction of polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol with dialkyl carbonate, dialkylene carbonate, diphenyl carbonate, and the like. Two or more types of polycarbonate-based polyols may be used in combination.

[0016] Vegetable oil-based polyols are preferred polyols for polyurethane foams for sealing materials because they mix well with hydrophobic polyether polyols and are effective in exhibiting hydrophobic properties. Vegetable oil-based polyols include those derived from castor oil, sunflower oil, rapeseed oil, linseed oil, cottonseed oil, tung oil, palm oil, poppy seed oil, corn oil, nut oil, etc. Castor oil-based polyols and nut oil-based polyols are preferred.

[0017] Examples of castor oil-based polyols include castor oil, reaction products of castor oil with polyols, and esterification products of castor oil fatty acids with polyols. Examples of polyols to be reacted with castor oil or castor oil fatty acids include dihydric polyols such as ethylene glycol, diethylene glycol, and propylene glycol, and trihydric or higher polyols such as glycerin, trimethylolpropane, hexanetriol, and sorbitol. The castor oil-based polyol preferably has 2 to 3 functional groups and a molecular weight of 300 to 3,000, more preferably 500 to 1,000. Examples of nut-based polyols include peanut-based and cashew-based polyols. The nut-based polyol preferably has 2 to 3 functional groups and a molecular weight of 300 to 3,000, more preferably 500 to 1,000. Two or more types of vegetable oil-based polyols may be used in combination. Oil-based polyols without reactive groups are also effective.

[0018] The foam stabilizer may be any known foam stabilizer for polyurethane foam. Examples include silicone-based foam stabilizers, fluorine-based foam stabilizers, and known surfactants. The amount of foam stabilizer is determined appropriately, but an example is 0.01 to 12 parts by weight per 100 parts by weight of the polyol component.

[0019] The catalyst may be an amine catalyst or an organometallic catalyst for polyurethane foam, either alone or in combination. Examples of the amine catalyst include monoamine compounds, diamine compounds, triamine compounds, polyamine compounds, cyclic amine compounds, alcohol amine compounds, and ether amine compounds. These may be used alone or in combination. Examples of the organometallic catalyst include organotin compounds, organoiron compounds, organobismuth compounds, organolead compounds, and organozinc compounds. These may be used alone or in combination. The amount of catalyst is determined as appropriate, but is typically 0.05 to 5 parts by weight per 100 parts by weight of the polyol component.

[0020] The core-shell rubber particles are polymer particles having a core-shell structure in which the surface of a particulate core component is partially or entirely coated with a shell component. The particle size of the core-shell rubber particles is preferably a volume average particle diameter of 10 to 2,000 nm, more preferably 50 to 800 nm, even more preferably 100 to 600 nm, and particularly preferably 200 to 400 nm. The core-shell rubber particles are preferably contained in an amount of 0.5 to 5.0 wt % in the polyurethane reaction composition excluding the isocyanate component. If the amount of the core-shell rubber particles is too small, it becomes difficult to achieve a low compression set. On the other hand, if the amount of the core-shell rubber particles is too large, the foaming state of the polyurethane foam decreases and the cost increases.

[0021] To facilitate mixing with the polyol component, the core-shell rubber particles are preferably added to the polyurethane reaction composition as a core-shell rubber particle dispersion in which the core-shell rubber particles are dispersed in polypropylene glycol. The core-shell rubber particle dispersion preferably has a core-shell rubber particle:polypropylene glycol (weight ratio) of 40:60 to 50:50. The polypropylene glycol in the core-shell rubber particle dispersion functions as a solvent.

[0022] Optional additives may also be added to the polyurethane reaction composition, such as chain extenders, crosslinkers, fillers, dyes, pigments, antioxidants, and flame retardants. Examples of the chain extender include polyethylene glycol (PEG), dipropylene glycol (DPG), etc. When a chain extender is added, the amount of the chain extender is preferably 0.5 to 20 parts by weight per 100 parts by weight of the polyol component. Examples of crosslinking agents include polyhydric alcohols such as glycerin, butanetetraol, and polypropylene glycol, diethanolamine, and polyamine. When a crosslinking agent is added, the amount of the crosslinking agent is preferably 0.5 to 10 parts by weight per 100 parts by weight of the polyol component. Examples of fillers include alumina trihydrate, silica, talc, calcium carbonate, clay, and the like.

[0023] The isocyanate component may be any of aromatic, alicyclic, and aliphatic isocyanates, and may also be a bifunctional isocyanate having two isocyanate groups in one molecule, or a trifunctional or higher isocyanate having three or more isocyanate groups in one molecule, and these may be used alone or in combination.

[0024] For example, bifunctional isocyanates include 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate (TDI), m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 2,4'-diphenylmethane diisocyanate (MDI), 2,2'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3 Examples of the isocyanate include aromatic isocyanates such as 1,3'-dimethoxy-4,4'-biphenylene diisocyanate, alicyclic isocyanates such as cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, and methylcyclohexane diisocyanate, and aliphatic isocyanates such as butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, and lysine isocyanate.

[0025] Furthermore, examples of difunctional or higher isocyanates include polymethylene polyphenylisocyanate (polymeric MDI). Examples of trifunctional or higher isocyanates include 1-methylbenzene-2,4,6-triisocyanate, 1,3,5-trimethylbenzene-2,4,6-triisocyanate, biphenyl-2,4,4'-triisocyanate, diphenylmethane-2,4,4'-triisocyanate, methyldiphenylmethane-4,6,4'-triisocyanate, 4,4'-dimethyldiphenylmethane-2,2',5,5'tetraisocyanate, and triphenylmethane-4,4',4"-triisocyanate. The isocyanate is not limited to one type, and may be one or more types. For example, one type of aliphatic isocyanate and two types of aromatic isocyanate may be used in combination. The isocyanate index is preferably 90 to 110. 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 by [(isocyanate equivalent in the foaming raw material / active hydrogen equivalent in the foaming raw material) x 100].

[0026] The foam-forming gas is preferably a gas that does not adversely affect the reaction between the polyol and the isocyanate, such as dry air or nitrogen. The foam-forming gas is preferably a gas that produces polyurethane foam with an apparent density of 100 to 800 kg / m. 3 The amount of foam-forming gas used is preferably such that the foaming ratio is 10 to 1.4 times, and more specifically, the mixing ratio of the foam-forming gas in the polyurethane reaction composition is preferably 31 to 91% by volume. The mixing ratio of the foam-forming gas refers to the volume % of the foam-forming gas relative to 100 parts by volume of the polyurethane reaction composition excluding the foam-forming gas.

[0027] The polyurethane foam of the present invention is produced by the mechanical froth method, in which a mixed raw material obtained by compressing and mixing a foam-forming gas into a polyurethane reaction composition is fed into an O-X mixer or a nozzle with a tapered tip and discharged from the O-X mixer or nozzle. The mixed raw material may be discharged continuously onto a release paper or by a molding method into a mold.

[0028] The polyurethane foam of the present invention has a 25% CLD hardness (25% compression load) of 0.05 MPa or less, preferably 0.04 MPa or less, according to the JIS K6400-2D method. Since the polyurethane foam of the present invention has a 25% CLD hardness of 0.05 MPa or less, when used as a sealing material by being compressed between two objects, it adheres closely to both objects by compression, providing good sealing properties.

[0029] The polyurethane foam of the present invention has a compression set of 10% or less according to JIS K6400-4. Because the polyurethane foam of the present invention has a low compression set of 10% or less, when used as a sealing material between two objects in compression for a long period of time, it can prevent sealing defects from occurring.

[0030] The polyurethane foam of the present invention has low air permeability and is suitable as a sealing material, for example, when the polyurethane foam is formed into a ring shape and provided on the inner periphery of a lid that covers a container body, and is compressed between the container body and the lid to form a seal between them, or when the polyurethane foam is provided at the joint between two objects and is compressed between the two objects to form a seal.

[0031] The breathability test for the polyurethane foam of the present invention is carried out as follows: A sample is prepared by punching out a 2 mm thick polyurethane foam into a ring (annular) shape with an outer diameter of 38 mm, an inner diameter of 34 mm, and a thickness of 2 mm, as shown in Figure 1, and the sample is set in the sample setting position of the breathability measurement chamber shown in Figure 2.

[0032] The air permeability measurement chamber has a tubular pressing part on its top surface that is connected to the outside and protrudes toward the sample setting position inside the measurement chamber. The tubular pressing part compresses the outer periphery of the sample's central hole, allowing the central hole of the sample to communicate with the outside of the measurement chamber. By replacing the tubular pressing part, the distance between the underside of the tubular pressing part and the sample setting position inside the measurement chamber (the amount of compression of the sample) can be adjusted.

[0033] The outer periphery of the central hole of the sample placed in the measurement chamber is compressed at a predetermined compression ratio between the underside of the tubular pressing part and the bottom of the measurement chamber, and the compressed part seals the space between the inside of the tubular pressing part and the measurement chamber. The compression ratio (%) of the sample is calculated by [(original thickness - thickness after compression) / original thickness × 100].

[0034] With the outer periphery of the sample compressed, nitrogen gas is supplied into the measurement chamber to increase the pressure inside the chamber. When the pressure inside the measurement chamber reaches 10 kPa, the supply of nitrogen gas into the measurement chamber is stopped. The nitrogen gas inside the measurement chamber enters the sample from the side of the outer periphery and gradually escapes to the outside of the measurement chamber through the central hole of the sample, causing the pressure inside the measurement chamber to gradually increase. The time from when the supply of nitrogen gas into the measurement chamber is stopped (pressure inside the measurement chamber is 10 atmospheres) to when the pressure inside the measurement chamber drops to 5 kPa is measured as the ventilation time. The polyurethane foam of the present invention has an air permeability time of 240 seconds or more at a compression rate of 30%, and has good low air permeability.

[0035] The polyurethane foam of the present invention has an apparent density (in accordance with JIS K 7222:2005) of 200 to 500 kg / m 3 If the apparent density of the polyurethane foam is too low or too high, when it is compressed between two objects, the adhesion to both objects decreases, resulting in a decrease in sealing ability.

[0036] When the polyurethane foam of the present invention is used as a sealing material, it is formed into, for example, a ring (O-ring) shape by punching or molding, or a shape that fits into the joint between two objects. [Example]

[0037] The following raw materials were used to prepare a polyurethane reaction composition having the formulation shown in the tables of Figures 3 and 4, with a foam-forming gas (nitrogen) added at a mixing ratio of 85% by volume. The mixture was mixed and stirred in a mechanical froth foaming machine, and the mixture was continuously discharged onto release paper and heated to 120 to 240°C to produce a 2 mm thick sheet-like polyurethane foam. Polyol 1: Polyether polyol, product name: PP-3000, manufactured by Sanyo Chemical Industries, Ltd., molecular weight 3000, number of functional groups 3, propylene oxide content 100% Polyol 2: Castor oil-based polyol, product name: HS 3G-500B, manufactured by Toyokuni Oil Mills, molecular weight 2500, number of functional groups 2.2 Polyol 3: Castor oil-based polyol, product name: HS CM-025P, manufactured by Toyokuni Oil Mills, molecular weight 840, number of functional groups 3 Polyol 4: Cashew nut-based polyol, product name: NX-9203, manufactured by Cardolite, molecular weight 1350, number of functional groups 2 Chain extender: Dipropylene glycol Core-shell rubber particle dispersion 1: Product name: MX-714, manufactured by Kaneka Corporation, core-shell rubber particles / polypropylene glycol (molecular weight 400) = 40 / 60 weight ratio Core-shell rubber particle dispersion 2: Product name: MX-710, manufactured by Kaneka Corporation, core-shell rubber particles / polypropylene glycol (molecular weight 1000) = 40 / 60 weight ratio Crosslinking agent: Glycerin Metal catalyst: Organic acid salt catalyst, product name: EP73660A, manufactured by PANTECHNOLOGY Foam stabilizer: Silicone foam stabilizer, product name: SZ-1952, manufactured by Dow Corning Toray Isocyanate: Polymeric MDI (crude MDI), product name: M5S, manufactured by BASF Inoac Polyurethanes, NCO%: 34%

[0038] The numerical values ​​for each component in the polyurethane reaction composition columns of the tables in FIGS. 3 and 4 are in parts by weight, and the total amount is the total amount of the polyurethane reaction composition excluding the isocyanate component. The core-shell rubber particle content is the content of core-shell rubber particles contained in the total amount (the total amount of the polyurethane reaction composition excluding the isocyanate component), and is the value expressed as a percentage obtained by calculating the amount of rubber particles in the core-shell rubber particle dispersion and dividing it by the total amount (the total amount of the polyurethane reaction composition excluding the isocyanate component).

[0039] For each example and comparative example, the apparent density (kg / m 3 ), breathability (seconds), compression set (%), and 25% CLD hardness (MPa) were measured, and evaluations were made for each measurement result and an overall evaluation.

[0040] The apparent density was measured in accordance with JIS K 7222:2005. The breathability (seconds) was measured at a compression rate of 50% and a compression rate of 30% according to the above-mentioned breathability measurement method. The breathability evaluation was rated as "x" if the breathability was greater than 1800 seconds at a compression rate of 50% and greater than 180 seconds at a compression rate of 30%, and as "◎" if the breathability was 1800 seconds or less at a compression rate of 50% and 180 seconds or less at a compression rate of 30%.

[0041] Compression set (%) was calculated according to JIS K6400-4 by compressing a 2 mm thick sample by 50% in the thickness direction, leaving it to stand at a predetermined temperature (70°C) for 22 hours, and then measuring the thickness of the sample 30 minutes after releasing the compressive stress at room temperature (23°C), using the following formula: Compression set (%) = [(thickness before compression - thickness after release) / thickness before compression] x 100 The compression set evaluation was as follows: if the compression set was 20% or more, it was marked "x", if it was 15 to less than 20%, it was marked "△", if it was 8 to less than 15%, it was marked "◯", and if it was less than 8%, it was marked "◎".

[0042] The 25% CLD hardness (MPa) is the compressive stress when a sample with a thickness of 2 mm is compressed by 25% at a rate of 1 mm / min in accordance with the JIS K6400-2D method. The 25% CLD hardness was evaluated as follows: if the 25% CLD hardness was more than 0.04 MPa, it was marked "x", if it was more than 0.03 and not more than 0.04, it was marked "good", and if it was not more than 0.03, it was marked "excellent". The 25% CLD hardness increase rate of each Example and Comparative Example was calculated as a percentage of the 25% CLD hardness value (100%) of Comparative Example 1, in which the amount of core-shell rubber particles and crosslinking agent was 0 parts by weight, and evaluated. The 25% CLD hardness increase rate was evaluated as "×" if it was 150% or more, "◯" if it was 115 to less than 150%, and "◎" if it was less than 115%.

[0043] The overall rating was determined by the lowest rating among the individual ratings. In other words, if there was even one "x" in each rating, the overall rating was "x," if the lowest rating among the ratings was "△," the overall rating was "△," if the lowest rating among the ratings was "〇," and if all the ratings were "◎," the overall rating was "◎."

[0044] <Example using core-shell rubber particle dispersion 1> Example 1-1 Example 1-1 is an example in which the polyol components were 49.0 parts by weight of Polyol 1, 10.0 parts by weight of Polyol 2, 17.0 parts by weight of Polyol 3, and 20.0 parts by weight of Polyol 4, 3.0 parts by weight of Chain Extender, 2.0 parts by weight of Core-Shell Rubber Particle Dispersion 1, 0 parts by weight of Crosslinker, 4.0 parts by weight of Metal Catalyst, and 8.0 parts by weight of Foam Stabilizer, and isocyanate was blended to an Isocyanate Index of 103. In Example 1-1, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 0.71% by weight.

[0045] The polyurethane foam of Example 1-1 has an apparent density of 290 kg / m 3The breathability was 1800 seconds or more at a compression rate of 50% and 302 seconds at a compression rate of 30%, rated as "◎", the compression set was 14.0%, rated as "◯", the 25% CLD hardness was 0.027 MPa, rated as "◎", the 25% CLD hardness increase rate was 103%, rated as "◎", and the overall rating was "◯". The polyurethane foam of Example 1-1 contained 0.71 wt% core-shell rubber particles, and therefore had low hardness, low breathability, and low compression set.

[0046] Example 1-2 Example 1-2 is an example in which the amounts of Polyol 1 and Core-shell Rubber Particle Dispersion 1 in Example 1-1 were changed to 48.0 parts by weight and 3.0 parts by weight, respectively, and the other components were the same as those in Example 1-1. In Example 1-2, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 1.06% by weight.

[0047] The polyurethane foam of Example 1-2 has an apparent density of 286 kg / m 3 The breathability was 1800 seconds or more at a compression rate of 50% and 298 seconds at a compression rate of 30%, rated as "◎", the compression set was 9.4%, rated as "◯", the 25% CLD hardness was 0.028 MPa, rated as "◎", the 25% CLD hardness increase rate was 105%, rated as "◎", and the overall rating was "◯". The polyurethane foam of Example 1-2 had a higher core-shell rubber particle content than Example 1-1, and therefore had a smaller compression set and a slightly higher 25% CLD hardness than Example 1-1, but had low hardness, low breathability, and low compression set.

[0048] Examples 1-3 Example 1-3 is an example in which, in Example 1-1, the amount of Polyol 1 was 47.0 parts by weight, the amount of Core-shell Rubber Particle Dispersion 1 was 4.0 parts by weight, and the other components were the same as in Examples 1-1 and 1-2. In Example 1-3, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 1.42% by weight.

[0049] The polyurethane foam of Examples 1-3 has an apparent density of 292 kg / m 3The breathability was 1800 seconds or more at a compression rate of 50% and 306 seconds at a compression rate of 30%, rated as "◎", the compression set was 8.8%, rated as "◯", the 25% CLD hardness was 0.029 MPa, rated as "◎", the 25% CLD hardness increase rate was 111%, rated as "◎", and the overall rating was "◯". The polyurethane foam of Example 1-3 had a higher core-shell rubber particle content than Examples 1-1 and 1-2, and therefore had a smaller compression set and a slightly higher 25% CLD hardness than Examples 1-1 and 1-2, but had low hardness, low breathability, and low compression set.

[0050] Examples 1-4 Example 1-4 is an example in which, in Example 1-1, the amount of Polyol 1 was 45.0 parts by weight, the amount of Core-shell Rubber Particle Dispersion 1 was 6.0 parts by weight, and the other components were the same as in Examples 1-1 to 1-3. In Example 1-4, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 2.12% by weight.

[0051] The polyurethane foam of Examples 1-4 has an apparent density of 285 kg / m 3 The breathability was 1800 seconds or more at a compression rate of 50% and 288 seconds at a compression rate of 30%, rated as "◎", the compression set was 6.9%, rated as "◎", the 25% CLD hardness was 0.031 MPa, rated as "◯", and the 25% CLD hardness increase rate was 117%, rated as "◯", resulting in an overall rating of "◯". The polyurethane foam of Example 1-4 had a higher core-shell rubber particle content than Examples 1-1 to 1-3, and therefore had a smaller compression set and a slightly higher 25% CLD hardness than Examples 1-1 to 1-3, but had low hardness, low breathability, and low compression set.

[0052] Examples 1-5 Example 1-5 is an example in which, in Example 1-1, the amount of Polyol 1 was 43.0 parts by weight, the amount of Core-shell Rubber Particle Dispersion 1 was 8.0 parts by weight, and the other components were the same as in Examples 1-1 to 1-4. In Example 1-5, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 2.83% by weight.

[0053] The polyurethane foam of Examples 1-5 has an apparent density of 282 kg / m 3 The breathability was 1800 seconds or more at a compression rate of 50% and 299 seconds at a compression rate of 30%, rated as "◎", the compression set was 5.3%, rated as "◎", the 25% CLD hardness was 0.032 MPa, rated as "◯", and the 25% CLD hardness increase rate was 122%, rated as "◯", resulting in an overall rating of "◯". The polyurethane foam of Example 1-5 had a higher core-shell rubber particle content than Examples 1-1 to 1-4, and therefore had a smaller compression set and a slightly higher 25% CLD hardness than Examples 1-1 to 1-4, but had low hardness, low breathability, and low compression set.

[0054] Examples 1-6 Example 1-6 is an example in which, in Example 1-1, the amount of Polyol 1 was 41.0 parts by weight, the amount of Core-shell Rubber Particle Dispersion 1 was 10.0 parts by weight, and the other components were the same as in Examples 1-1 to 1-5. In Example 1-6, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 3.54% by weight.

[0055] The polyurethane foams of Examples 1-6 have an apparent density of 277 kg / m 3 The breathability was 1800 seconds or more at a compression rate of 50% and 271 seconds at a compression rate of 30%, rated as "◎", the compression set was 5.2%, rated as "◎", the 25% CLD hardness was 0.034 MPa, rated as "◯", and the 25% CLD hardness increase rate was 130%, rated as "◯", resulting in an overall rating of "◯". The polyurethane foam of Example 1-6 had a higher core-shell rubber particle content than Examples 1-1 to 1-5, and therefore had a smaller compression set and a slightly higher 25% CLD hardness than Examples 1-1 to 1-5, but had low hardness, low breathability, and low compression set.

[0056] <Example using core-shell rubber particle dispersion 2> Example 2-1 Example 2-1 is an example in which the polyol components were 49.0 parts by weight of Polyol 1, 10.0 parts by weight of Polyol 2, 17.0 parts by weight of Polyol 3, and 20.0 parts by weight of Polyol 4, 3.0 parts by weight of Chain Extender, 2.0 parts by weight of Core-Shell Rubber Particle Dispersion 2, 0 part by weight of Crosslinker, 4.0 parts by weight of Metal Catalyst, and 8.0 parts by weight of Foam Stabilizer, and isocyanate was blended to an Isocyanate Index of 103. In Example 2-1, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 0.71% by weight.

[0057] The polyurethane foam of Example 2-1 has an apparent density of 301 kg / m 3 The breathability was 1800 seconds or more at a compression rate of 50% and 298 seconds at a compression rate of 30%, rated as "◎", the compression set was 12.2%, rated as "◯", the 25% CLD hardness was 0.026 MPa, rated as "◎", the 25% CLD hardness increase rate was 98%, rated as "◎", and the overall rating was "◯". The polyurethane foam of Example 2-1 had low hardness, low breathability, and low compression set because the core-shell rubber particle content was 0.71% by weight.

[0058] Example 2-2 Example 2-2 is an example in which, in Example 2-1, the amount of Polyol 1 was 48.0 parts by weight, the amount of Core-shell Rubber Particle Dispersion 2 was 3.0 parts by weight, and the other components were the same as in Example 2-1. In Example 2-2, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 1.06% by weight.

[0059] The polyurethane foam of Example 2-2 has an apparent density of 293 kg / m 3The breathability was 1800 seconds or more at a compression rate of 50% and 305 seconds at a compression rate of 30%, rated as "◎", the compression set was 8.5%, rated as "◯", the 25% CLD hardness was 0.027 MPa, rated as "◎", the 25% CLD hardness increase rate was 102%, rated as "◎", and the overall rating was "◯". The polyurethane foam of Example 2-2 had a higher core-shell rubber particle content than Example 2-1, and therefore had a smaller compression set and a slightly higher 25% CLD hardness than Example 2-1, but had low hardness, low breathability, and low compression set.

[0060] Example 2-3 Example 2-3 is an example in which, in Example 2-1, the amount of Polyol 1 was 47.0 parts by weight, the amount of Core-shell Rubber Particle Dispersion 2 was 4.0 parts by weight, and the other components were the same as in Examples 2-1 and 2-2. In Example 2-3, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 1.42% by weight.

[0061] The polyurethane foam of Example 2-3 has an apparent density of 296 kg / m 3 The breathability was 1800 seconds or more at a compression rate of 50% and 290 seconds at a compression rate of 30%, rated as "◎", the compression set was 7.2%, rated as "◎", the 25% CLD hardness was 0.027 MPa, rated as "◎", and the 25% CLD hardness increase rate was 102%, rated as "◎", and the overall rating was "◎". The polyurethane foam of Example 2-3 had a higher core-shell rubber particle content than Examples 2-1 and 2-2, and therefore had a smaller compression set and a slightly higher 25% CLD hardness than Examples 2-1 and 2-2, but had low hardness, low breathability, and low compression set.

[0062] Example 2-4 Example 2-4 is an example in which, in Example 2-1, the amount of Polyol 1 was 45.0 parts by weight, the amount of Core-shell Rubber Particle Dispersion 2 was 6.0 parts by weight, and the other components were the same as in Examples 2-1 to 2-3. In Example 2-4, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 2.12% by weight.

[0063] The polyurethane foam of Example 2-4 has an apparent density of 290 kg / m 3 The breathability was 1800 seconds or more at a compression rate of 50% and 311 seconds at a compression rate of 30%, rated as "◎", the compression set was 6.9%, rated as "◎", the 25% CLD hardness was 0.028 MPa, rated as "◎", and the 25% CLD hardness increase rate was 106%, rated as "◎", and the overall rating was "◎". The polyurethane foam of Example 2-4 had a higher core-shell rubber particle content than Examples 2-1 to 2-3, and therefore had a smaller compression set and a slightly higher 25% CLD hardness than Examples 2-1 to 2-3, but had low hardness, low breathability, and low compression set.

[0064] Example 2-5 Example 2-5 is an example in which, in Example 2-1, the amount of Polyol 2 was 43.0 parts by weight, the amount of Core-shell Rubber Particle Dispersion 2 was 8.0 parts by weight, and the other components were the same as in Examples 2-1 to 2-4. In Example 2-5, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 2.83% by weight.

[0065] The polyurethane foam of Example 2-5 has an apparent density of 288 kg / m 3 The breathability was 1800 seconds or more at a compression rate of 50% and 272 seconds at a compression rate of 30%, rated as "◎", the compression set was 4.6%, rated as "◎", the 25% CLD hardness was 0.029 MPa, rated as "◎", and the 25% CLD hardness increase rate was 110%, rated as "◎", and the overall rating was "◎". The polyurethane foam of Example 2-5 had a higher core-shell rubber particle content than Examples 2-1 to 2-4, and therefore had a smaller compression set and a slightly higher 25% CLD hardness than Examples 2-1 to 2-4, but had low hardness, low breathability, and low compression set.

[0066] Example 2-6 Example 1-6 is an example in which, in Example 2-1, the amount of Polyol 1 was 41.0 parts by weight, the amount of Core-shell Rubber Particle Dispersion 2 was 10.0 parts by weight, and the other components were the same as in Examples 2-1 to 2-5. In Example 2-6, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 3.54% by weight.

[0067] The polyurethane foam of Example 2-6 has an apparent density of 292 kg / m 3 The breathability was 1800 seconds or more at a compression rate of 50% and 255 seconds at a compression rate of 30%, rated as "◎", the compression set was 4.4%, rated as "◎", the 25% CLD hardness was 0.030 MPa, rated as "◎", and the 25% CLD hardness increase rate was 114%, rated as "◎", and the overall rating was "◎". The polyurethane foam of Example 2-6 had a higher core-shell rubber particle content than Examples 2-1 to 2-5, and therefore had a smaller compression set and a slightly higher 25% CLD hardness than Examples 2-1 to 2-5, but had low hardness, low breathability, and low compression set.

[0068] <Comparative Example Not Containing Core-Shell Rubber Particle Dispersion> Comparison Example 1 Comparative Example 1 is an example in which the polyol components were 51.0 parts by weight of Polyol 1, 10.0 parts by weight of Polyol 2, 17.0 parts by weight of Polyol 3, and 20.0 parts by weight of Polyol 4, 3.0 parts by weight of chain extender, 0 part by weight of core-shell rubber particle dispersion, 0 part by weight of crosslinking agent, 4.0 parts by weight of metal catalyst, 8.0 parts by weight of foam stabilizer, and isocyanate was blended to an isocyanate index of 103. In Comparative Example 1, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 0.00% by weight.

[0069] The polyurethane foam of Comparative Example 1 has an apparent density of 295 kg / m 3The breathability was 1800 seconds or more at a compression rate of 50% and 320 seconds at a compression rate of 30%, rated as "◎", the compression set was 31.0%, rated as "×", the 25% CLD hardness was 0.026 MPa, rated as "◎", the 25% CLD hardness increase rate was 100%, rated as "◎", and the overall rating was "×". The polyurethane foam of Comparative Example 1 has a core-shell rubber particle content of 0.00% by weight, so it has a larger compression set than the other Examples, and when used as a sealing material, gaps may occur in the sealing area during use, resulting in poor sealing.

[0070] Comparative Example 2 Comparative Example 2 is an example in which the amounts of Polyol 1 and crosslinking agent in Comparative Example 1 were changed to 48.0 parts by weight and 3.0 parts by weight, respectively, and the other components were the same as those in Comparative Example 1. In Comparative Example 2, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 0.00% by weight.

[0071] The polyurethane foam of Comparative Example 2 has an apparent density of 235 kg / m 3 The breathability was 1800 seconds or more at a compression rate of 50% and 285 seconds at a compression rate of 30%, rated as "◎", the compression set was 5.3%, rated as "◎", the 25% CLD hardness was 0.058 MPa, rated as "×", and the 25% CLD hardness increase rate was 219%, rated as "×", resulting in an overall rating of "×". The polyurethane foam of Comparative Example 2 contained 3.0 parts by weight of crosslinking agent compared to Comparative Example 1, which reduced the compression set, but increased the 25% CLD hardness, so when used as a sealing material, poor compression could cause gaps in the sealed area, resulting in poor sealing.

[0072] Comparative Example 3 Comparative Example 3 is an example in which the amount of Polyol 1 was 46.0 parts by weight and the amount of crosslinking agent was 5.0 parts by weight in Comparative Example 1, and the other components were the same as in Comparative Examples 1 and 2. In Comparative Example 3, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 0.00% by weight.

[0073] The polyurethane foam of Comparative Example 3 has an apparent density of 233 kg / m 3The breathability was 1800 seconds or more at a compression rate of 50% and 266 seconds at a compression rate of 30%, rated as "◎", the compression set was 5.3%, rated as "◎", the 25% CLD hardness was 0.0096 MPa, rated as "×", and the 25% CLD hardness increase rate was 362%, rated as "×", resulting in an overall rating of "×". The polyurethane foam of Comparative Example 3 contained 5.0 parts by weight of crosslinking agent compared to Comparative Example 1, which reduced the compression set, but increased the 25% CLD hardness, so when used as a sealing material, poor compression could cause gaps in the sealed area, resulting in poor sealing. Comparative Example 4 Comparative Example 4 is an example in which the amounts of polyol 1, polyol 2, polyol 3, polyol 4, and foam stabilizer in Comparative Example 1 were changed to 52.0 parts by weight, 10.0 parts by weight, 30.0 parts by weight, 8.0 parts by weight, and 6.0 parts by weight, respectively, and the other components were the same as those in Comparative Example 1. In Comparative Example 4, the total amount of the polyurethane reaction composition excluding the isocyanate component was 113.0 parts by weight, and the core-shell rubber particle content was 0.00% by weight.

[0074] The polyurethane foam of Comparative Example 4 had an apparent density of 323 kg / m 3 The breathability was 236 seconds at a compression rate of 50% and 7 seconds at a compression rate of 30%, rated as "×", the compression set was 6.2%, rated as "◎", the 25% CLD hardness was 0.020 MPa, rated as "◎", and the 25% CLD hardness increase rate was 75.8%, rated as "◎", and the overall rating was "×". The polyurethane foam of Comparative Example 4 has high breathability due to the increased amount of polyol 1 and the decreased amount of polyol 4 compared to Comparative Example 1, and is therefore unsuitable as a sealing material.

[0075] As described above, the polyurethane foam of the present invention has low hardness, low air permeability and low compression set, and is therefore suitable as a sealing material.

Claims

1. A polyurethane foam obtained from a polyurethane reaction composition containing a polyol component, a foam stabilizer, a catalyst, and an isocyanate component, The polyol component includes a polyether polyol, a castor oil-based polyol, and a cashew nut-based polyol, the polyurethane reaction composition includes core-shell rubber particles; Apparent density according to JIS K 7222:2005 is 200 kg / m ３ ~500 kg / m ３ and A polyurethane foam characterized by being obtained by a mechanical frothing method using a foam-forming gas.

2. 2. The polyurethane foam according to claim 1, wherein the compression set according to JIS K6400-4 is less than 20%.

3. A sealing material comprising the polyurethane foam according to claim 1 or 2.

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