JP2006348156A - Method for producing rigid polyurethane foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a rigid polyurethane foam, capable of continuously producing the rigid polyurethane foam having an open-cell structure, capable of shortening an aging time, and therefore capable of being improved in productivity. <P>SOLUTION: In this method, the rigid polyurethane foam having the open-cell structure is continuously produced by continuously supplying a raw material 18 which contains polyols, polyisocyantes, a foaming agent, and a catalyst onto a traveling first belt conveyor 11, then reacting, foaming, and curing the raw material. A polyether polyol and a polyester polyol are used as the polyols. Further, a feed rate of the polyols, a traveling speed of the first belt conveyor 11, and a tilt angle α of the first belt conveyor 11 in a direction of traveling of the first belt conveyor 11 are set to be 40-60 kg/min, 3.5-5.5 m/min, and 0-3°, respectively. It is preferable that a height of a slab block 19 is 300-500 mm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention can be used, for example, as automotive parts such as automobile ceiling materials and sun visors, and can continuously produce a rigid polyurethane foam excellent in performance such as sound absorption and shorten the cooling time to room temperature. The present invention relates to a method for producing a rigid polyurethane foam.

  Generally, since a hard polyurethane foam has closed cells, physical properties such as sound absorption are low. On the other hand, in recent years, the demand for hard polyurethane foams having an open cell structure has been increasing for heat insulating materials used for automobile parts such as ceiling materials and sun visors in order to impart sound absorption. The rigid polyurethane foam having such an open cell structure has a high exothermic temperature at the time of foaming, and exceeds the dissociation temperature of the urethane bond (150 ° C. or higher) and the dissociation temperature of the urea bond (180 ° C. or higher), and can spontaneously ignite. There is sex. For this reason, foaming is carried out so as to suppress the heat generation temperature using trichlorofluoromethane (CFC11), methylene chloride or the like during the continuous bubble formation. However, trichlorofluoromethane, methylene chloride, and the like are substances that adversely affect the environment, such as ozone layer destruction, and their use is being regulated.

Therefore, a method for producing a rigid polyurethane foam using water as a foaming agent and adopting a predetermined formulation has been proposed. Specifically, a manufacturing method of a rigid polyurethane foam that can be molded at room temperature with open cells is disclosed (for example, see Patent Document 1). That is, a polyisocyanate mixture of about 70 to 90% by weight diphenylmethane diisocyanate and about 10 to 30% by weight polyphenyl polymethylene polyisocyanate is converted to a difunctional and / or trifunctional hydroxyl polyether and a difunctional phthalate. In this method, acid hydroxyl polyester, glycerin, water, and a tertiary amine catalyst are reacted.
JP-A-4-21416 (pages 2 and 5)

  In the technique described in the above-mentioned Patent Document 1, since the rigid polyurethane foam is manufactured by supplying the raw material into a reaction vessel and batch operation, the batch operation is repeated in manufacturing the rigid polyurethane foam product. There is a problem that productivity is low. At that time, the cream time in which the raw material exists in a liquid state is about 60 to 80 seconds, and thereafter the gel time until the reaction and curing proceed to solidify is about 200 to 260 seconds, both of which are long. Accordingly, there is a problem that the manufacturing time per batch becomes long and the manufacturing efficiency is poor. Furthermore, since foaming is performed in the reaction vessel, the internal heat generation temperature at the time of foaming becomes very high, and it takes about 2 days for the time to decrease to room temperature after foaming, that is, the aging time is about 2 days (see Patent Document 1 5 page), there was a problem of poor productivity.

  Accordingly, an object of the present invention is to provide a rigid polyurethane foam capable of continuously producing a rigid polyurethane foam having an open-cell structure and shortening the aging time and improving the productivity. It is in providing the manufacturing method of a body.

  In order to achieve the above object, the method for producing a rigid polyurethane foam according to claim 1 moves a raw material of the rigid polyurethane foam containing polyols, polyisocyanates, a blowing agent and a catalyst. A method of continuously producing a rigid polyurethane foam having an open cell structure by continuously supplying and reacting on a conveyor, foaming and curing, and using polyether polyol and polyester polyol as the polyols In addition, the supply amount of polyols is 40 to 60 kg / min, the moving speed of the conveyor is 3.5 to 5.5 m / min, and the inclination angle of the conveyor in the moving direction of the conveyor is 0 so that the horizontal or the downstream side in the moving direction is low. It is characterized by being set to ˜3 °.

  A method for producing a rigid polyurethane foam according to a second aspect of the present invention is characterized in that, in the first aspect of the present invention, the height of the foamed foam is 300 to 500 mm.

  According to a third aspect of the present invention, there is provided a method for producing a rigid polyurethane foam according to the first or second aspect, wherein an amine catalyst having a hydroxyl group is used as the catalyst and an addition reaction between a polyamine and an alkylene oxide. A crosslinker having an autocatalytic action, which is obtained and made of a polyol having a plurality of terminal hydroxyl groups, is blended.

  The method for producing a rigid polyurethane foam according to claim 4 is the invention according to any one of claims 1 to 3, wherein the polyester polyol is a phthalic acid having a hydroxyl value of 200 to 400 mgKOH / g. It is a glycol ester.

  The method for producing a rigid polyurethane foam of the invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the polyisocyanate for the active hydrogen groups of the polyols, the foaming agent or the crosslinking agent. Isocyanate index which represents the equivalent ratio of the isocyanate group of a kind in percentage is 100-110, It is characterized by the above-mentioned.

  The method for producing a rigid polyurethane foam according to claim 6 is the invention according to any one of claims 1 to 5, wherein the polyisocyanate is composed mainly of polyphenylpolymethylene polyisocyanate. , A polyisocyanate containing diphenylmethane diisocyanate.

According to the present invention, the following effects can be exhibited.
In the method for producing a rigid polyurethane foam according to the first aspect of the present invention, the raw material of the rigid polyurethane foam is continuously supplied on the moving conveyor to be reacted, foamed and cured. Therefore, a rigid polyurethane foam can be manufactured continuously. In that case, since the supply amount of polyols is set to 40 to 60 kg / min and the moving speed of the conveyor is set to 3.5 to 5.5 m / min, the relative relationship between the supply amount of polyols and the moving speed of the conveyor is set. The thickness of the raw material on the conveyor is suppressed. And since the inclination-angle of the conveyor in the moving direction of a conveyor is set to 0-3 degree so that the horizontal or the moving direction downstream side may become low, progress of foaming can be suppressed. For this reason, the height of the foam by foaming is suppressed and cooling to the normal temperature of a foam is promoted. Therefore, the aging time of the foam can be shortened and productivity can be improved.

  In addition, since the polyether polyol and the polyester polyol have low compatibility, the cell membrane is broken by the polyols in the foaming process of the raw material of the hard polyurethane foam, and a cell communication structure is formed. For this reason, the rigid polyurethane foam can have an open cell structure.

  In the method for producing a rigid polyurethane foam of the invention according to claim 2, since the height of the foam by foaming is set to a low value of 300 to 500 mm, in addition to the effect of the invention according to claim 1, the foam Can be sufficiently shortened.

  The method for producing a rigid polyurethane foam according to claim 3 uses an amine catalyst having a hydroxyl group as a catalyst, and is an autocatalyst comprising a polyol having a plurality of terminal hydroxyl groups obtained by addition reaction of polyamine and alkylene oxide. A crosslinking agent having an action is blended. For this reason, the crosslinking agent is an amine-based compound and has an autocatalytic action, and the urethanization reaction is promoted together with the amine catalyst. Therefore, in addition to the effect of the invention according to claim 1 or 2, the rigid polyurethane foam can be produced efficiently and continuously.

  In the method for producing a rigid polyurethane foam of the invention according to claim 4, the polyester polyol is a phthalic acid glycol ester having a hydroxyl value of 200 to 400 mgKOH / g. Since this phthalic acid glycol ester has a benzene ring, it can exhibit hardness (rigidity). Therefore, in addition to the effects of the invention according to any one of claims 1 to 3, the hardness of the rigid polyurethane foam can be improved.

  In the method for producing a rigid polyurethane foam of the invention according to claim 5, since the isocyanate index is 100 to 110, in addition to the effects of the invention according to claims 1 to 4, A crosslinking density can be made appropriate and sufficient hardness can be obtained.

  In the method for producing a rigid polyurethane foam according to claim 6, the polyisocyanate is a polyisocyanate containing polyphenyl polymethylene polyisocyanate as a main component and diphenylmethane diisocyanate. For this reason, in addition to the effect of the invention according to any one of claims 1 to 5, there is no risk of polyisocyanates solidifying during the production of the hard polyurethane foam, and the workability can be improved. The body can be manufactured easily.

Hereinafter, embodiments of the present invention will be described in detail.
The rigid polyurethane foam having an open cell structure in the present embodiment (hereinafter also simply referred to as a foam) is produced as follows. That is, such a rigid polyurethane foam is produced by continuously supplying a raw material of a rigid polyurethane foam containing polyols, polyisocyanates, a foaming agent and a catalyst onto a moving conveyor to react, foam, and harden. Are continuously manufactured. At that time, polyether polyol and polyester polyol are used as polyols, the supply amount of polyols is 40 to 60 kg / min, the moving speed of the conveyor is 3.5 to 5.5 m / min, and the conveyor in the moving direction of the conveyor Is set to 0 to 3 ° so that the horizontal or the downstream side in the moving direction becomes lower. In addition, it is preferable that the width | variety of a conveyor is 1000-1500 mm in order to maintain productivity of a rigid polyurethane foam. When this width is less than 1000 mm, the effect of continuously producing a rigid polyurethane foam cannot be obtained sufficiently. On the other hand, when it exceeds 1500 mm, it is difficult to adjust the height of the foam by the supply amount of polyols, the speed of the conveyor, the inclination angle of the conveyor, etc., which is not preferable.

  Specifically, referring to the drawings, as shown in FIG. 1, the first belt conveyor 11 having an inclination angle α so as to become lower in the traveling direction (from left to right in FIG. 1) has a height of It is supported on different support platforms 12 and 13. At the front (downstream side) position of the first belt conveyor 11, a second belt conveyor 14 extending in the horizontal direction is supported on support platforms 15 and 16 having the same height. A raw material supply device 17 is disposed above the rear (upstream side) of the first belt conveyor 11, and the raw material 18 is discharged onto the first belt conveyor 11 and foamed to form a foam (slab block) 19. It is like that. The length of the first belt conveyor 11 is set to a length necessary for completing the foaming of the raw material 18, and at least the slab block 19 is set to a length necessary for foaming to a predetermined height and stabilizing.

  Here, the rigid polyurethane foam of the present embodiment means a foam having an open-cell structure, plastically deformed with respect to compressive force, and having no resilience. In the above manufacturing process, the thickness of the raw material on the conveyor is suppressed by the relative relationship between the supply amount of polyols and the moving speed of the conveyor, and the inclination angle α of the conveyor is set to be nearly horizontal, The progress of foaming can be suppressed, the height of the foam can be suppressed, and the aging time (cooling time) of the foam can be shortened. Moreover, since the compatibility of the polyester polyol with the polyether polyol is low, it is considered that the produced cell membrane is broken and the cells communicate with each other, and an open cell structure is formed.

First, the raw material of the said rigid polyurethane foam is demonstrated.
As the polyols, a polyether polyol and a polyester polyol are used in combination. As a result, the polyether polyol and the polyester polyol have low compatibility, and the cell membrane is broken during the foaming process so that the cells communicate with each other. Examples of the polyether polyol include polypropylene glycol, polytetramethylene glycol, polyether polyol made of a polymer obtained by addition polymerization of propylene oxide and ethylene oxide to a polyhydric alcohol, and modified products thereof. Examples of the polyhydric alcohol include glycerin, trimethylolpropane, dipropylene glycol and the like.

  Specific examples of polyether polyols include triols obtained by addition polymerization of propylene oxide to glycerin and addition polymerization of ethylene oxide, and diols obtained by addition polymerization of propylene oxide to dipropylene glycol and addition polymerization of ethylene oxide. . The polyethylene oxide unit in the polyether polyol is about 10 to 30 mol%. When the content of the polyethylene oxide unit is large, the hydrophilicity is higher than when the content is low, the miscibility with polyisocyanates having high polarity is improved, and the reactivity is increased. The polyether polyol can be used in combination with a plurality of types to adjust the number of functional groups and the hydroxyl value of the hydroxyl group.

  On the other hand, as polyester polyol, in addition to condensed polyester polyol obtained by reacting polycarboxylic acid such as phthalic acid and adipic acid with polyol such as ethylene glycol, diethylene glycol, propylene glycol and glycerin, lactone polyester polyol and Polycarbonate-based polyols are used. For example, a phthalic acid glycol ester having a hydroxyl value of 200 to 400 mgKOH / g is preferably used. When the hydroxyl value is less than 200 mgKOH / g, the crosslink density of the polyurethane foam is low, and the hardness and strength of the foam tend to decrease. On the other hand, when the hydroxyl value exceeds 400 mgKOH / g, the crosslink density increases, the foam becomes hard, and the cell connectivity also decreases. By using a polycarboxylic acid having an aromatic ring such as phthalic acid, the hardness (rigidity) of the obtained rigid polyurethane foam can be improved.

  The polyols preferably have a functional group number in the range of 2.0 to 3.5, and a hydroxyl value in the range of 20 to 400 mgKOH / g. However, when a plurality of polyols having different numbers of functional groups or different hydroxyl values are used, the average number of functional groups or the average hydroxyl value is preferably within the above range. The average number of functional groups or the average hydroxyl value is a value obtained by averaging the number of functional groups or the hydroxyl value of each polyol according to the blending ratio. By using polyols having such a functional group number and hydroxyl value, the reactivity between polyols and polyisocyanates is excellent, and foaming and crosslinking proceed in a well-balanced manner to obtain the desired rigid polyurethane foam. Can do.

  When the number of functional groups of the polyols is less than 2.0, the crosslinking reaction is not sufficiently performed, and the strength of the rigid polyurethane foam tends to decrease. On the other hand, when the number of functional groups exceeds 3.5, foaming is not performed smoothly, cell connectivity is poor, and it becomes difficult to obtain a rigid polyurethane foam having an open cell structure. Furthermore, when the hydroxyl value of polyols is less than 20 mgKOH / g, the hydroxyl value becomes too small, and the crosslinking density of the polyurethane foam tends to be low, and the hardness and strength of the foam tend to decrease. On the other hand, when the hydroxyl value exceeds 400 mgKOH / g, the crosslinking density becomes too high, the foam becomes hard, and the connectivity of the cells also decreases. These polyols can change the number of functional groups and the hydroxyl value of the hydroxyl group by adjusting the type, molecular weight, condensation degree, and the like of the raw material components.

  Subsequently, a cross-linking agent having an autocatalytic action is used to form a cross-linked structure in a hard polyurethane foam by cross-linking reaction with polyisocyanates and to improve physical properties such as hardness and strength. A polyol obtained by an addition reaction with an oxide and having a plurality of terminal hydroxyl groups is used. Since this crosslinking agent is based on an amine in addition to the crosslinking action, it has an autocatalytic action. Examples of the polyamine include ethylenediamine and triethylenediamine. Examples of the alkylene oxide include propylene oxide and ethylene oxide. And an alkylene oxide is used excessively with respect to a polyamine, and addition reaction is performed so that the polyol obtained may have two or more terminal hydroxyl groups. Since the polyols also have a plurality of hydroxyl groups, they have a crosslinking action but do not have an autocatalytic action.

  The polyisocyanates to be reacted with the above polyols are compounds having a plurality of isocyanate groups. Specifically, tolylene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (MDI), modified MDI, polymeric MDI, 1 , 5-naphthalene diisocyanate (NDI), triphenylmethane triisocyanate, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI), and modified products thereof.

  Specifically, it is preferable to use polyisocyanate (crude MDI) containing polyphenyl polymethylene polyisocyanate (polymeric MDI) as a main component and containing diphenylmethane diisocyanate (monomeric MDI). Monomeric MDI coagulates at 10 ° C., but can be kept liquid by using polymeric MDI as a main component. Therefore, workability at the time of manufacturing the rigid polyurethane foam can be improved, and the manufacture of the rigid polyurethane foam can be facilitated.

  The isocyanate index (isocyanate index) of the polyisocyanates may be 100 or less or more than 100, but is preferably 100 to 110. Here, the isocyanate index represents the equivalent ratio of the isocyanate groups of the polyisocyanate to the polyols, water as a foaming agent, or active hydrogen groups of the crosslinking agent, in percentage. When the isocyanate index is less than 100, the crosslink density of the rigid polyurethane foam is lowered, and the hardness and strength are lowered. On the other hand, when the isocyanate index exceeds 110, the crosslink density of the rigid polyurethane foam becomes high, the hardness becomes too high, and the connectivity of the cells also decreases. The polyisocyanates are preferably aromatic polyisocyanates in order to improve physical properties such as hardness and strength of the rigid polyurethane foam.

The foaming agent is for foaming the raw material to form a rigid polyurethane foam. For example, pentane, cyclopentane, hexane, cyclohexane, dichloromethane, carbon dioxide gas, etc. are used in addition to water. Of these foaming agents, water is preferable because it can react quickly with polyisocyanates to generate sufficient carbon dioxide gas and can be handled easily. When the foaming agent is water, the blending amount is preferably 2 to 5 parts by mass with respect to 100 parts by mass of polyols in order to adjust the density of the rigid polyurethane foam to 30 to 50 kg / m ³ . When the amount of water is less than 2 parts by mass, the foaming reaction is insufficient, the amount of foaming is small, the density of the hard polyurethane foam tends to be higher than 50 kg / m ³ , and the cell connectivity tends to be poor. Show. On the other hand, if it exceeds 5 parts by mass, the temperature tends to rise due to heat generation during foaming and curing, and it becomes difficult to lower the temperature, and the density of the rigid polyurethane foam becomes a low density of less than 30 kg / m ^3. Tend to decrease in strength.

  The catalyst is for accelerating the urethanization reaction between polyols and polyisocyanates. As this catalyst, an amine catalyst having a hydroxyl group is used. By using this catalyst together with the crosslinking agent having the autocatalytic action, the urethanization reaction can be sufficiently promoted, and the production efficiency can be increased. Specific examples of the amine catalyst include N, N-dimethylaminohexanol, N, N-dimethylaminoethoxyethoxyethanol, trimethylaminoethylethanolamine, and the like. A foam stabilizer, a filler, a stabilizer, a colorant, a flame retardant, a plasticizer, and the like are blended with the raw material of the rigid polyurethane foam as necessary. Examples of the foam stabilizer include silicone compounds, anionic surfactants such as sodium dodecylbenzenesulfonate and sodium lauryl sulfate, polyether siloxane, and phenolic compounds.

  And the hard polyurethane foam is manufactured by making the raw material of the hard polyurethane foam mentioned above react, and making it foam and harden | cure. In this rigid polyurethane foam, a raw material (liquid raw material) mixed and stirred is continuously supplied onto a moving conveyor, and while the conveyor moves, the raw material spontaneously foams and reacts at normal temperature and atmospheric pressure. It is manufactured continuously. As the conveyor, a belt conveyor is usually used. Examples of the belt include a rubber belt, a resin belt, and a metal belt. Thereafter, it is cured (cured) in a drying furnace and cut into a predetermined shape.

  In that case, the supply amount of polyols is 40 to 60 kg / min, the moving speed of the conveyors (first belt conveyor 11 and second belt conveyor 14) is 3.5 to 5.5 m / min, and the conveyor in the moving direction of the conveyor. Is set to 0 to 3 ° so that the horizontal or the downstream side in the moving direction becomes lower. Furthermore, the width of the conveyor is set to 1000 to 1500 mm. The supply amount of the polyols and the moving speed of the conveyor are in a relative relationship, and the thickness of the raw material on the conveyor can be suppressed as the supply amount of the polyols is decreased and the moving speed of the conveyor is increased. In this embodiment, the thickness of the raw material on a conveyor is suppressed by setting to said range. When the conveyor is inclined, the raw material is fed to a high position on the conveyor. Therefore, foaming and reaction proceed while the raw material flows from the high position of the conveyor to the low position. In this case, the raw material foams and cures vertically upward regardless of the inclination of the conveyor. The foaming direction of the obtained slab block is theoretically inclined by the inclination angle α of the conveyor, but it is not necessary to consider such inclination substantially.

  When the supply amount of polyols is less than 40 kg / min or the moving speed of the conveyor exceeds 5.5 m / min, the thickness of the raw material on the conveyor becomes too thin, and sufficient foaming and reaction cannot be obtained. On the other hand, when the supply amount of polyols exceeds 60 kg / min or the moving speed of the conveyor is less than 3.5 m / min, the thickness of the raw material on the conveyor becomes too thick and the foaming height becomes high. The aging time representing the cooling of the foam to room temperature becomes longer. Also, when the conveyor inclination angle α in the moving direction of the conveyor exceeds 3 °, the liquid raw material tends to flow from the high side to the low side of the conveyor, and it is necessary to relatively slow the moving speed of the conveyor. As a result, the height of the foam becomes too high, and heat storage in the slab block increases, so that the aging time of the foam becomes long.

  In the foaming process, the liquid raw material is raised by the foaming reaction to form a foam, and the height (thickness) of the foam is preferably 300 to 500 mm. By maintaining the height of such a foam to be low, the aging time of the foam can be sufficiently shortened. When the height of the foam is less than 300 mm, sufficient foaming and reaction are not performed. On the other hand, when the height of the foam exceeds 500 mm, the temperature inside the foam rises, it takes time for cooling, and the aging time tends to be long.

  The reaction during the production of the rigid polyurethane foam is complicated, and basically the following reaction is the main component. That is, addition polymerization reaction of polyols and polyisocyanates (urethanization reaction, resinification reaction), foaming (foaming) reaction of polyisocyanates with water as a blowing agent, and their reaction products, crosslinking agents and It is a curing (crosslinking) reaction with polyisocyanates. Resinification is performed with the progress of these addition polymerization reaction, foaming reaction and curing reaction.

  The resinification reaction and foaming are started after a state in which the raw material of the rigid polyurethane foam is kept in a liquid state (cream-like), in other words, after a time until the resinification reaction and foaming start (cream time). This cream time is preferably 20 to 40 seconds. Thereafter, the reaction of the raw material of the rigid polyurethane foam proceeds to increase the viscosity, causing resinification (gelling and forming a skeleton), and forming cells by foaming. The rigid polyurethane foam is manufactured through a time (rise time) from the injection of the hard polyurethane foam raw material until the foaming is most advanced and the foaming height is the highest. The rise time is preferably 80 to 120 seconds. By setting the cream time and the rise time to such a short time, a rigid polyurethane foam can be produced continuously and efficiently.

  When producing a rigid polyurethane foam, a one-shot method in which a polyol and a polyisocyanate are directly reacted, or a polyol and a polyisocyanate are reacted in advance to obtain a prepolymer having an isocyanate group at the terminal. Any of the prepolymer methods in which polyols are reacted therewith can be employed.

The rigid polyurethane foam produced in this manner has a closed cell ratio specified by ASTM D 2856 of 1% or less and an air flow rate specified by JIS L 1096 of 1.0 to 5.0 ml / cm. ² · sec is preferable. In this case, the rigid polyurethane foam has an open cell structure in which cells communicate with each other and has high air permeability. Further, the rigid polyurethane foam preferably has a density of 30 to 50 kg / m ³ and an Asker C hardness of 20 to 50. In this case, the rigid polyurethane foam can exhibit sufficient density and strength as a foam. The Asker C hardness is a value measured based on the provisions of SRIS0101 (Japan Rubber Association Standard).

  Now, to explain the operation of the present embodiment, as shown in FIG. 1, the raw material 18 of the rigid polyurethane foam is continuously discharged and reacted on the first belt conveyor 11 moving from the raw material supply device 17, The slab block 19 is continuously manufactured by foaming and hardening. At that time, the supply amount of polyols is suppressed to 40 to 60 kg / min, and at the same time, the moving speed of the first belt conveyor 11 is set to a high speed of 3.5 to 5.5 m / min. The thickness of the raw material 18 on the conveyor 11 is suppressed to, for example, 500 mm or less. And since the inclination angle (alpha) of the 1st belt conveyor 11 is set to the angle close | similar to the horizontal of 0-3 degrees, the situation where the raw material 18 flows to the lower side and foaming advances is suppressed. For this reason, excessive foaming is suppressed, cooling from the periphery of the slab block 19 acts effectively, and cooling to room temperature is performed quickly.

  Further, the polyester polyol in the raw material 18 of the rigid polyurethane foam has low compatibility with the polyether polyol, and as the cells are formed in the foaming process of the raw material 18, the polyester polyol separates from the polyether polyol and forms a cell membrane. Presumed to act to break. Therefore, the cells of the foam are communicated, and properties such as air permeability are exhibited.

  In addition, the cross-linking agent is an amine-based compound that exhibits an autocatalytic action, promotes the urethanization reaction with the amine-based catalyst, and continuously produces a rigid polyurethane foam. At that time, since these crosslinking agents and catalysts both have a hydroxyl group, they react with the polyisocyanates in the production process and are incorporated into the skeleton of the polyurethane, so that the odor of the amine compound is encased. Therefore, the diffusion of amine odor is suppressed.

The effects exhibited by the above embodiment will be described collectively below.
-In the manufacturing method of the rigid polyurethane foam in this embodiment, it is carried out by supplying the raw material of a rigid polyurethane foam continuously on the moving conveyor, making it react, and foaming and hardening. Therefore, a rigid polyurethane foam can be manufactured continuously. In that case, since the supply amount of polyols is set to 40 to 60 kg / min and the moving speed of the conveyor is set to 3.5 to 5.5 m / min, the relative relationship between the supply amount of polyols and the moving speed of the conveyor is set. The thickness of the raw material on the conveyor is suppressed. And since the inclination-angle (alpha) of the conveyor in the moving direction of a conveyor is set to 0-3 degrees so that the horizontal or the moving direction downstream side may become low, progress of foaming can be suppressed. For this reason, the height of a foam is suppressed and cooling to the normal temperature of a foam is promoted. Therefore, the aging time of the foam can be shortened and productivity can be improved.

  In addition, since the polyether polyol and the polyester polyol have low compatibility, the cell membrane is broken in the foaming process of the raw material of the hard polyurethane foam, and a cell communication structure is formed. For this reason, the rigid polyurethane foam can have an open cell structure.

  Furthermore, by suppressing the height of the foam obtained by foaming to a low height of 300 to 500 mm, the aging time of the foam can be sufficiently shortened by the cooling action from the periphery of the foam.

  In addition, an amine catalyst having a hydroxyl group is used as a catalyst, and a cross-linking agent having a self-catalytic action, which is obtained by an addition reaction between a polyamine and an alkylene oxide and is composed of a polyol having a plurality of terminal hydroxyl groups, is blended. For this reason, a urethanation reaction is accelerated | stimulated based on the cooperation effect | action of the autocatalytic action by a crosslinking agent, and the catalytic action by an amine catalyst. Therefore, a rigid polyurethane foam can be manufactured efficiently and continuously.

  -The hardness based on a benzene ring is expressed by using the phthalic acid glycol ester whose hydroxyl value is 200-400 mgKOH / g as a polyester polyol in the raw material of a rigid polyurethane foam. Therefore, the hardness of the rigid polyurethane foam can be improved.

-Moreover, by setting an isocyanate index to 100-110, the crosslinking density of a rigid polyurethane foam can be made appropriate, and sufficient hardness can be obtained.
-As a polyisocyanate in the raw material of a rigid polyurethane foam, it is preferable to use polyisocyanate containing polyphenyl polymethylene polyisocyanate as a main component and diphenylmethane diisocyanate. In that case, there is no possibility that polyisocyanates solidify during the production of the rigid polyurethane foam, workability can be improved, and the rigid polyurethane foam can be easily produced.

Hereinafter, the embodiment will be described more specifically with reference to examples and comparative examples, but the invention is not limited to these examples.
(Examples 1 to 6 and Comparative Examples 1 and 2)
First, the raw materials of the rigid polyurethane foam in each Example and Comparative Example were prepared in the blending amounts shown in Tables 1 and 2. Each raw material of the rigid polyurethane foam in Table 1 and Table 2 represents part by mass. The raw materials for rigid polyurethane foams such as polyols, polyisocyanates, crosslinking agents, foaming agents, foam stabilizers and catalysts used in the examples and comparative examples are shown below.

  Polyether polyol # 5000: Polyether polyol obtained by addition reaction of propylene oxide and ethylene oxide with glycerin, functional group number 3, hydroxyl value 33 (mgKOH / g), molecular weight 5000.

  Polyether polyol: Polyether polyol obtained by addition reaction of propylene oxide and ethylene oxide with glycerin, functional group number 3, hydroxyl value 250 mgKOH / g, molecular weight 670.

Phthalic acid glycol ester: Polyester polyol obtained by adding diethylene glycol to phthalic anhydride, functional group number 2, hydroxyl value 260 mgKOH / g, molecular weight 430.
Crude MDI: A mixture of 70% by mass of polyphenylpolymethylene polyisocyanate and 30% by mass of diphenylmethane diisocyanate.

EDP300: Polyol obtained by adding propylene oxide to ethylenediamine, number of functional groups 4, hydroxyl value 740 mgKOH / g, molecular weight 300, manufactured by Asahi Denka Kogyo Co., Ltd.
KAO-25: N, N-dimethylaminohexanol, manufactured by Kao Corporation.

Foam stabilizer: Polyoxyalkylene dimethylpolysiloxane, a continuous foam stabilizer for rigid polyurethane foam, manufactured by Toray Dow Corning, SZ1949.
Subsequently, the raw materials of the hard polyurethane foams of Examples and Comparative Examples shown in Tables 1 and 2 were mixed and stirred. And the rigid polyurethane foam was manufactured with the manufacturing apparatus shown in FIG. That is, the raw material 18 was discharged onto the first belt conveyor 11 under the conditions shown in Tables 1 and 2. When the first belt conveyor 11 is inclined, the raw material 18 was discharged to a high position at the rear of the first belt conveyor 11. While the first belt conveyor 11 moved, the raw material 18 spontaneously foamed at normal temperature and atmospheric pressure, and reacted to continuously manufacture the slab block 19. The speeds of the first belt conveyor 11 and the second belt conveyor 14 are the same. Thereafter, it was cured (cured) in a drying furnace to obtain a hard slab polyurethane foam. As reaction conditions, the addition amount of a crosslinking agent having an autocatalytic function and an amine catalyst was adjusted so that the cream time was 20 to 40 seconds and the rise time was 80 to 120 seconds. Moreover, the width | variety of the 1st belt conveyor 11 and the 2nd belt conveyor 14 was set to 1500 mm in Example 1-5, and 1000 mm in Example 6. FIG.

The obtained hard slab polyurethane foam was cut out to obtain a sheet-like hard polyurethane foam. About this rigid polyurethane foam, foam height, aging time, density, hardness (Asker C hardness), elongation, air flow rate, sound absorption rate, maximum temperature, heat release rate, discoloration, cream time, rise time and health bubble are as follows: It measured according to the measuring method. The results are shown in Tables 1 and 2.
(Measuring method)
Supply amount of polyols (kg / min): Total supply amount of polyether polyol # 5000, polyether polyol and phthalic acid glycol ester.

Conveyor speed (m / min): The moving speed of the conveyor per minute was set.
Inclination angle (°) of first belt conveyor: The inclination angle α of the first belt conveyor 11 in the traveling direction of the first belt conveyor 11 was set.

Foam height (mm): The highest height of the foam obtained by foaming was measured.
Aging time (Hr): The time from when the temperature inside the foam (in the center) rose after foaming until it reached room temperature (25 ° C.) was measured.

Density (kg / m ³ ): Measured according to JIS K 7222: 1999.
Hardness (Asker C hardness): Measured based on SRIS0101 (Japan Rubber Association Standard).

Elongation (%): Measured according to JIS K 6400-5: 2004.
Aeration rate (ml / cm ² · sec): Measured according to JIS L 1096. However, the thickness of the sheet-like rigid polyurethane foam used as a measurement sample was set to 5.5 mm.

Sound absorption rate (%): Measured according to JIS A 1405 (normal incidence sound absorption rate).
Maximum temperature (° C.): The maximum temperature inside the foam (center) was measured.
Heat release rate (° C / Hr): The average rate from the start of dropping from the maximum temperature to the normal temperature was measured.

  Discoloration (ΔYI): Color difference meter (SM color computer SM-4, manufactured by Suga Test Instruments Co., Ltd.) for the foamed part (center part) and the low-temperature part (side part) during foaming and curing. Were used to measure the yellowing degree (whiteness) and indicated by their color difference (ΔYI).

Cream time (second): The raw polyurethane foam was kept in a liquid state (cream), and the time until the resinification reaction and foaming started was measured.
Rise time (seconds): The time from when the raw material of the rigid polyurethane foam was injected to when the foaming progressed most and the foaming height became the highest was measured.

  Health Bubble: In the manufacturing process of rigid polyurethane foam, the foaming state is visually confirmed, and “Yes” is indicated when bubbles are released from the foam, and “No” is indicated when bubbles are not released from the foam. evaluated.

表１に示したように、実施例１〜５においては、発泡高さが３５０〜４８０ｍｍに抑えられ、熟成時間を１２〜２０時間に短縮することができた。従って、発泡を行った翌日には発泡体の加工を行うことができる。また、クリームタイムが２５〜３５秒で、ライズタイムが１１０〜１２０秒であり、製造時間を短くすることができた。さらに、ヘルスバブル及び通気量の結果から硬質ポリウレタン発泡体は連続気泡構造を有していることが示され、吸音率が良好であった。また、硬質ポリウレタン発泡体は十分な架橋構造が形成され、十分な硬さが得られた。加えて、実施例６においては、第１ベルトコンベヤ１１及び第２ベルトコンベヤ１４の幅を１０００ｍｍに設定したが、ポリオール類の供給量を４０ｋｇ／ｍｉｎに減少させることで、実施例１〜５と同様の良好な発泡体を得ることができた。

As shown in Table 1, in Examples 1 to 5, the foaming height was suppressed to 350 to 480 mm, and the aging time could be shortened to 12 to 20 hours. Therefore, the foam can be processed the next day after foaming. Further, the cream time was 25 to 35 seconds and the rise time was 110 to 120 seconds, and the production time could be shortened. Furthermore, the results of the health bubble and the air flow rate showed that the rigid polyurethane foam had an open cell structure, and the sound absorption coefficient was good. Further, the rigid polyurethane foam had a sufficient cross-linked structure and a sufficient hardness. In addition, in Example 6, although the width | variety of the 1st belt conveyor 11 and the 2nd belt conveyor 14 was set to 1000 mm, by reducing the supply amount of polyols to 40 kg / min, Example 1-5 and Similar good foams could be obtained.

  On the other hand, as shown in Table 2, in Comparative Example 1, the speed of the first belt conveyor 11 was decreased and the inclination angle α was increased, so that the foaming height reached 700 mm and the aging time was 35 hours. It took time. Furthermore, since the heat dissipation rate was as low as 4 ° C./Hr and the maximum temperature reached 175 ° C., the discoloration (ΔYI) was 11. In Comparative Example 2, since the blending amount of the phthalic acid glycol ester was increased, the connectivity of the foam increased, the air flow increased, oxygen was introduced into the center of the foam, and the color change (ΔYI) was 36. It became high. Further, since the speed of the first belt conveyor 11 was decreased and the inclination angle α was increased, the foaming height reached 700 mm and the aging time required a long time of 30 hours.

In addition, this embodiment can also be changed and embodied as follows.
・ As the conveyor, a conveyor such as a fluid conveyor can be used in addition to the belt conveyor.

-It is also possible to supply the raw material of rigid polyurethane foam to a plurality of locations on the conveyor.
-As the polyester polyol, a plurality of types having different functional groups and hydroxyl values of the hydroxyl group can be used in combination.

A small amount of tertiary amine such as triethylenediamine or dimethylethanolamine, acetate, etc. can be used as a catalyst.
Further, the technical idea that can be grasped from the embodiment will be described below.

  The method for producing a rigid polyurethane foam according to any one of claims 1 to 6, wherein the polyether polyol is obtained by addition polymerization of propylene oxide and ethylene oxide to glycerin. According to this production method, in addition to the effects of the invention according to any one of claims 1 to 6, the reactivity between the polyether polyol and the polyisocyanate can be improved.

  The method for producing a rigid polyurethane foam according to any one of claims 1 to 6, wherein the foaming agent is water. According to this production method, in addition to the effects of the invention according to any one of claims 1 to 6, the reactivity between the polyisocyanates and water is good, and foaming can be performed effectively.

Schematic explanatory drawing which shows the manufacturing apparatus of a rigid polyurethane foam.

Explanation of symbols

  11 ... 1st belt conveyor as a conveyor, 14 ... 2nd belt conveyor as a conveyor, 18 ... Raw material of a rigid polyurethane foam.

Claims (6)

A rigid polyurethane foam having an open-cell structure by continuously supplying a raw material of a rigid polyurethane foam containing polyols, polyisocyanates, a foaming agent and a catalyst onto a moving conveyor to cause reaction and foaming and curing. A process for continuously producing
Polyether polyol and polyester polyol are used as the polyols, the supply amount of polyols is 40 to 60 kg / min, the moving speed of the conveyor is 3.5 to 5.5 m / min, and the conveyor is inclined in the moving direction of the conveyor. A method for producing a rigid polyurethane foam, characterized in that the angle is set to 0 to 3 ° so that the horizontal side or the downstream side in the moving direction is lowered. The method for producing a rigid polyurethane foam according to claim 1, wherein a height of the foamed foam is 300 to 500 mm. 2. An amine catalyst having a hydroxyl group is used as the catalyst, and a cross-linking agent obtained by an addition reaction between a polyamine and an alkylene oxide and having a self-catalytic action comprising a polyol having a plurality of terminal hydroxyl groups is blended. Or the manufacturing method of the rigid polyurethane foam of Claim 2. The method for producing a rigid polyurethane foam according to any one of claims 1 to 3, wherein the polyester polyol is a phthalic acid glycol ester having a hydroxyl value of 200 to 400 mgKOH / g. The isocyanate index which represents the equivalent ratio of the isocyanate group of the polyisocyanate with respect to the active hydrogen group of the polyol, foaming agent or crosslinking agent as a percentage is 100 to 110. The method for producing a rigid polyurethane foam according to one item. 6. The rigid polyurethane foam according to claim 1, wherein the polyisocyanate is a polyisocyanate containing polyphenyl polymethylene polyisocyanate as a main component and containing diphenylmethane diisocyanate. 7. Production method.

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