WO2022209853A1

WO2022209853A1 - Polyisocyanurate foam

Info

Publication number: WO2022209853A1
Application number: PCT/JP2022/011614
Authority: WO
Inventors: 聖末谷
Original assignee: 株式会社東洋クオリティワン
Priority date: 2021-03-29
Filing date: 2022-03-15
Publication date: 2022-10-06
Also published as: JP2022152057A

Abstract

In an embodiment of the present invention, a polyisocyanurate foam is provided. The polyisocyanurate foam is obtained by foaming a reaction system containing a polyol, a polyisocyanate, a foam stabilizer, a catalyst, and a foaming agent. The polyol includes a polyol A that has a weight average molecular weight within a range of 3000-12000 and has an ethylene oxide content of 50 wt% or more, and a polyol B that has a weight average molecular weight of 1000-8000 and has an ethylene oxide content less than 20 wt%. In the reaction system, the isocyanate index is 200-350. The coefficient of hystereisis loss is 90% or more.

Description

polyisocyanurate foam

The present invention relates to polyisocyanurate foams.

　Conventionally, in order to protect the safety of passengers against external impacts when riding in a car, shock absorbing materials are installed inside the doors, around the ceiling, and inside the pillars of the car. As shock absorbing materials, for example, rigid polyurethane foams and thermoplastic resin bead foams are known.

The shock absorbing materials installed in today's automobiles are required not only to have high shock absorption performance (buckling property), but also to have excellent sound absorption performance in order to increase the quietness inside the vehicle. Since rigid polyurethane foams and thermoplastic resin bead foams generally have a closed cell structure, even if they have a predetermined impact absorption performance, they may be inferior in sound absorption performance. Techniques for increasing the open-cell structure in order to improve the sound absorption performance of foams are known, but the impact-absorbing performance is inferior unless the open-cell structure is increased and the hardness of the foam is adjusted appropriately. Sometimes.

Japanese Patent Application Laid-Open No. 2013-047338 Japanese Patent Application Laid-Open No. 2005-272806 Japanese Patent No. 4461453

An object of the present invention is to provide a polyisocyanurate foam having excellent buckling property and predetermined sound absorbing performance.

According to one aspect of the present invention, a polyisocyanurate foam is provided. A polyisocyanurate foam is obtained by foaming in a reaction system containing a polyol, a polyisocyanate, a foam stabilizer, a catalyst and a blowing agent. The polyol has a weight average molecular weight in the range of 3000 to 12000 and an ethylene oxide content of 50% by weight or more, and a polyol having a weight average molecular weight of 1000 to 8000 and an ethylene oxide content of less than 20% by weight. B. The isocyanate index in the reaction system is 200 or more and 350 or less. Hysteresis loss rate is 90% or more. The hysteresis loss rate is obtained by cutting out a measurement sample having dimensions of 50 mm × 50 mm × 50 mm from the polyisocyanurate foam, and applying a load of 5 N to the measurement sample using a 80 φ compressor. Compress the polyisocyanurate foam along the foam height direction, and compress the measurement sample along the foam height direction at a rate of 50 mm/min until the thickness displacement from the reference thickness reaches 70%. Immediately thereafter, the measurement sample is returned along the foam height direction at a speed of 50 mm/min until the thickness displacement from the reference thickness reaches 0%.

According to the present invention, it is possible to provide a polyisocyanurate foam that has excellent buckling properties and a predetermined sound absorption performance.

The top view which shows an example of a polyisocyanurate foam roughly. FIG. 2 is a cross-sectional view schematically showing a cross section of the polyisocyanurate foam shown in FIG. 1 along line II-II. FIG. 2 is a cross-sectional view schematically showing a cross section of the polyisocyanurate foam shown in FIG. 1 along line III-III. 4 is a graph showing stress/displacement curves for polyisocyanurate foams according to the examples; 4 is a graph showing stress/displacement curves for polyisocyanurate foams according to the examples; 4 is a graph showing stress/displacement curves for polyisocyanurate foams according to the examples; 4 is a graph showing stress/displacement curves for polyisocyanurate foams according to the examples; 4 is a graph showing stress/displacement curves for polyisocyanurate foams according to the examples; 4 is a sound absorption coefficient graph showing measurement results of normal incident sound absorption coefficients for polyisocyanurate foams according to Examples. 4 is a sound absorption coefficient graph showing measurement results of normal incident sound absorption coefficients for polyisocyanurate foams according to Examples. 4 is a sound absorption coefficient graph showing measurement results of normal incident sound absorption coefficients for polyisocyanurate foams according to Examples. 4 is a sound absorption coefficient graph showing measurement results of normal incident sound absorption coefficients for polyisocyanurate foams according to Examples. 4 is a sound absorption coefficient graph showing measurement results of normal incident sound absorption coefficients for polyisocyanurate foams according to Examples.

Hereinafter, embodiments will be described with reference to the drawings as appropriate. In addition, the same code|symbol shall be attached|subjected to the common structure through embodiment, and the overlapping description is abbreviate|omitted. In addition, each drawing is a schematic diagram for explaining the embodiments and promoting understanding thereof, and there are places where the shapes, dimensions, ratios, etc. are different from the actual device, but these are the following explanations and known techniques. Consideration can be taken into consideration and the design can be changed as appropriate.

The impact absorption performance and sound absorption performance of polyisocyanurate foams vary depending on various factors, but in order to achieve the desired impact absorption performance and sound absorption performance, it is necessary to make the polyisocyanurate foams communicate with each other to a certain extent. . As a result, sound waves can easily propagate through the foam, and vibrational energy can be easily converted into thermal energy, thereby improving sound absorption performance. If the degree of communication is excessive or insufficient, the sound absorbing performance of the polyisocyanate foam deviates from the sound absorbing performance required by the present invention. In addition, in order to achieve high impact absorption performance, the polyisocyanurate foam, which is a porous elastic body, must have well-balanced hardness, density, communication, and the like.

The polyisocyanurate foam according to the embodiment is obtained by foaming in a reaction system containing two types of polyols having different properties and exhibiting a relatively high isocyanate index of 200 or more and 350 or less. When two polyols having different properties are reacted, the two polyols randomly react with isocyanate. In this case, uniform polyisocyanurate foams tend not to be formed as compared with, for example, the reaction of one type of polyol with isocyanate. Homogeneous polyisocyanurate foams are understood here to be membrane-rich foams. Each of the two polyols acts as a factor that degrades the uniformity of the foam in the formation of a myriad of urethane linkages. In other words, when two kinds of polyols having different properties are reacted with an isocyanate, there is a tendency to obtain a polyisocyanurate foam that is more interconnected.

By setting the isocyanate index in the reaction system within the range of 200 or more and 350 or less, an excessive amount of isocyanate is present in the system. Therefore, the remaining isocyanate is nurated (trimerized) to form more nurate structures than when the amount of isocyanate is smaller. A nurate structure is a structure in which three molecules of isocyanate form a ring. Therefore, the nurate structure also acts as a factor that lowers uniformity among countless urethane bonds. As a result, there are fewer membranes in the polyisocyanurate foam and a more open-ended foam is formed.

As described above, the polyisocyanurate foam according to the embodiment is communicated to a certain extent even when a separate communicating agent is not added to the reaction system, and as a result, it has a predetermined sound absorption performance. is doing. When no communication agent is added to the reaction system, it is advantageous from the viewpoint of cost and has the advantage of facilitating the handling of the polyol liquid during the production of the polyisocyanurate foam. Specifically, for example, if a communicating agent having poor hydrophilicity is used, it tends to separate from other components, resulting in poor handling. However, it is also possible to add a communicating agent to the reaction system according to the embodiment.

In addition, since the isocyanate index in the reaction system is within the range of 200 or more and 350 or less, the foam obtained as described above has many nurate structures. As the nurate structure increases, the polyisocyanurate foam becomes stiffer. A polyisocyanurate foam having a certain degree of hardness in addition to moderate communication can achieve excellent impact absorption performance, that is, a high hysteresis loss rate (90% or more). In other words, the polyisocyanurate foams according to embodiments exhibit excellent buckling properties. An increase in the nurate structure is preferred because it also increases the flame resistance and heat resistance of the polyisocyanurate foam.

The hysteresis loss rate of the polyisocyanurate foam may be 92% or higher, or 94% or higher. According to one example, the hysteresis loss rate is 99.0% or less. Although it cannot be determined only from the hysteresis loss rate, if the hysteresis loss rate is excessively high, there is a possibility that the predetermined sound absorption performance cannot be achieved. The predetermined sound absorption performance means that the target polyisocyanurate foam has a normal incidence sound absorption coefficient of 40% or more in the entire frequency range of 1000 Hz to 3150 Hz in the normal incidence sound absorption coefficient measurement described later. do.

If the isocyanate index in the reaction system is less than 200, the nurate structure may be insufficient and the hysteresis loss rate may be less than 90%. If the isocyanate index is more than 350, the moldability of the foam may deteriorate, and the desired sound absorbing performance may not be achieved.

<Method for measuring hysteresis loss rate>
The hysteresis loss rate of polyisocyanurate foam can be measured by the following method.

First, a measurement sample having dimensions of 50 mm x 50 mm x 50 mm is cut out from the polyisocyanurate foam to be measured. This sample is compressed using a compressor of 80φ to a reference thickness position where a load of 5N is applied. At that time, the polyisocyanurate foam as a measurement sample is compressed along the foam height direction. Next, the measurement sample is compressed at a speed of 50 mm/min until the thickness displacement from this reference thickness reaches 70%. The position where the thickness displacement reaches 70% is, in other words, the position where the thickness of the measurement sample in the compressed portion is 30% of the reference thickness.

After compressing until the thickness displacement reaches 70%, the measurement sample is immediately placed in a state where no pressure is applied, and the measurement sample is pressed at a speed of 50 mm / min until the thickness displacement from the reference thickness reaches 0%. return. The position where the thickness displacement reaches 0% is, in other words, the position where the thickness of the measurement sample is the same as the reference thickness.

The hysteresis loss rate is calculated according to Equation 1 below.
(S1-S2)/S1×100 (1)
Here, S1 is the sum of the stresses during compression from the reference thickness to the position where the thickness displacement reaches 70%, and S2 is the return from the position where the thickness displacement reaches 70% to the reference thickness. It is the sum of the stresses at time.

The polyisocyanurate foam according to the embodiment is obtained by foaming in a reaction system containing polyol, polyisocyanate, foam stabilizer, catalyst and foaming agent. The reaction system may further contain other additives such as antioxidants, plasticizers and the like. The reaction system may consist of only polyol, polyisocyanate, foam stabilizer, catalyst and blowing agent. In this case, for example, although the reaction system does not contain a communicating agent, the communicating effect can be obtained for the reason described above. Moreover, when the isocyanate index is in the range of 200 or more and 350 or less, the foam has many nurate structures, and the hysteresis loss rate of the polyisocyanurate foam can be 90% or more. From the viewpoint of realizing a three-dimensional shape and facilitating control of the cell structure, molding is preferable as the manufacturing method because it enables a three-dimensional uneven shape.

Each raw material is explained below.

(1) Polyol Polyol (also referred to as a polyol component) has a weight average molecular weight in the range of 3000 to 12000 and an ethylene oxide content of 50% by weight or more, and a polyol A having a weight average molecular weight of 1000 to 8000, and a polyol B having an ethylene oxide content of less than 20% by weight. The polyol component may contain other polyols different from polyol A and polyol B. The polyol component may consist of polyol A and polyol B only.

Polyol A has a weight average molecular weight within the range of 3000 to 12000 and an ethylene oxide content of 50% by weight or more. Since Polyol A contains ethylene oxide in an amount of 50% by weight or more, it has high polarity and high hydrophilicity. Polyol B, on the other hand, has a weight average molecular weight of 1000 to 8000 and an ethylene oxide content of less than 20% by weight. Polyol B, which has a low ethylene oxide content, has a low polarity compared to polyol A, and thus has low hydrophilicity. Since polyol A and polyol B have different properties, they have low compatibility among polyols.

The weight average molecular weight of polyol A is preferably in the range of 3000 or more and 9000 or less, more preferably in the range of 7000 or more and 9000 or less. When the weight average molecular weight of polyol A is less than 3000, the polyisocyanurate foam becomes highly brittle and may be unsuitable as a molded product. The ethylene oxide content of polyol A is preferably 60% by weight or more and 90% by weight or less, more preferably 65% by weight or more and 85% by weight or less. The hydroxyl value of Polyol A is, for example, 18 mgKOH/g or more and 52 mgKOH/g or less. Polyol A is, for example, a polyether polyol.

The ratio of the weight of polyol A to the weight of the polyol component is, for example, within the range of 50% to 90% by weight. When the ratio is within this range, good moldability, sound absorption performance and impact absorption performance can be achieved. When the ratio of polyol A is relatively high, the buckling property of the obtained polyisocyanurate foam tends to increase, for example, the stress at the time of return after compression tends to be small, which is preferable. The weight ratio of polyol A to the weight of the polyol component is preferably in the range of 65% to 85% by weight, more preferably in the range of 70% to 80% by weight.

The weight average molecular weight of polyol B is preferably in the range of 2000 or more and 8000 or less, more preferably in the range of 2500 or more and 7000 or less. If the weight average molecular weight of polyol B exceeds 8000, the hardness may be insufficient and the buckling property may be deteriorated. The ethylene oxide content of polyol B may be 0% by weight. That is, the ethylene oxide content of polyol B can be 0% or more and less than 20% by weight. Polyol B, which has a low ethylene oxide content, has a low polarity compared to polyol A, and thus has low hydrophilicity. Since polyol A and polyol B have different properties, they have low compatibility among polyols. If the ethylene oxide content of polyol B is 20% by weight or more, the compatibility with polyol A is high, so the degree of communication may be insufficient. The hydroxyl value of Polyol B is, for example, 20 mgKOH/g or more and 90 mgKOH/g or less.

The ratio of the weight of polyol B to the weight of the polyol component is, for example, within the range of 10% by weight to 50% by weight. When the ratio is within this range, good moldability, sound absorption performance and impact absorption performance can be achieved. The weight ratio of polyol B to the weight of the polyol component is preferably in the range of 15% to 35% by weight, more preferably in the range of 20% to 30% by weight.

The blending ratio of polyol A and polyol B in the polyol component can be determined by appropriately combining the multiple numerical ranges described above.

When the polyol component contains other polyols, the ratio of the total weight of polyol A and polyol B to the weight of the polyol component is preferably 80% by weight or more, more preferably 90% by weight or more.

The weight average molecular weight of polyol can be measured by size exclusion chromatography (SEC).

(2) Polyisocyanate As polyisocyanate, it is preferable to use diphenylmethane diisocyanate (MDI). Diphenylmethane diisocyanate may be monomeric MDI, polymeric MDI, or mixtures thereof. The polyisocyanate may contain only one type of MDI, or may contain two or more types. MDI is excellent in terms of molding because it has better curability than toluene diisocyanate (TDI).

(3) Foam Stabilizer The type of foam stabilizer is not particularly limited as long as the resulting polyisocyanurate foam has a hysteresis loss rate of 90% or more, but it may be a silicone foam stabilizer. In this case, since the foam stabilizing power is enhanced, the foaming gas generated by the reaction can be easily retained, and the effect of enhancing the moldability can be obtained.

The content of the foam stabilizer in the reaction system is, for example, within the range of 0.5 to 15 parts by weight with respect to 100 parts by weight of the polyol component. If the content of the foam stabilizer in the reaction system is too low, it will be difficult to retain the generated foaming gas, and moldability will tend to deteriorate. If the amount is too large, the foam-stabilizing power tends to be too high, resulting in a decrease in sound absorption performance. The content of the foam stabilizer in the reaction system is preferably in the range of 1.0 to 3.0 parts by weight with respect to 100 parts by weight of the polyol component.

(4) Catalyst As a catalyst, a resin catalyst, an isocyanurate catalyst (trimerization catalyst), a surface reforming catalyst, a foaming catalyst, and the like can be used. As each catalyst, a known catalyst used for that purpose can be used.

The resinification catalyst is used, for example, in an amount of 1 to 5 parts by weight based on the weight of the polyol component. The isocyanurating catalyst is used, for example, in an amount of 1 to 5 parts by weight based on the weight of the polyol component. The surface modification catalyst is used, for example, in an amount of 0.5 to 3 parts by weight based on the weight of the polyol component. The foaming catalyst is used, for example, in an amount of 0.1 to 1 part by weight based on the weight of the polyol component.

It is preferable to use diethanolamine (DEA) as the surface modification catalyst. DEA has OH groups at both ends and a secondary amine in the center. By cross-linking these OH groups and NH groups with the NCO groups possessed by the isocyanate, the strength of the skeleton of the resulting polyisocyanurate foam is increased, so that moldability is improved or stabilized, and peeling of the skin can be suppressed. .

(5) Foaming Agent As the foaming agent, any known foaming agent used for producing general polyisocyanurate foams or polyurethane foams can be used. The blowing agent in the present invention is water. The content of the foaming agent in the reaction system is preferably in the range of 5 to 20 parts by weight with respect to 100 parts by weight of the polyol component. In addition to water, commonly used auxiliary blowing agents may also be added. Examples of auxiliary blowing agents include freon and dichloromethane.

(6) Other Additives As other additives, for example, plasticizers and antioxidants can be added. The plasticizer can adjust the hardness and cell structure of the polyisocyanurate foam and improve the moldability. Antioxidants can suppress scorch. Other additives are used, for example, in amounts of 3 to 30 parts by weight based on the weight of the polyol component. Other additives can be used without limitation as long as they are used in the production of general polyisocyanurate foams or polyurethane foams.

The density of polyisocyanurate foams is, for example, in the range from 50 kg/m ³ to 100 kg/m ³ .

The compressive stress at 10% deformation of the polyisocyanurate foam is, for example, within the range of 0.5 kgf/cm ² to 4.0 kgf/cm ² .

In the present invention, the normal incident sound absorption coefficient of the polyisocyanurate foam is preferably 40% or more, more preferably 45% or more, over the entire frequency range of 1000 Hz to 3150 Hz. The normal incidence sound absorption coefficient is an index for evaluating sound absorption performance. As an example, when polyisocyanurate foam is used as a shock absorbing material for the lower limbs of automobiles, etc., if the normal incidence sound absorption coefficient is within the above range, it is difficult for the occupants of automobiles, etc., to perceive low-frequency noise. . Therefore, the occupants can be comfortable during the ride.

<Measurement of Normal Incidence Sound Absorption Coefficient>
The normal incident sound absorption coefficient of polyisocyanurate foam is measured by the following method.
First, a cylindrical polyisocyanurate foam lump having a diameter of 29 mm (29φ) and a thickness of 15 mm is prepared as an object for measuring the sound absorption coefficient. The mass can be prepared, for example, using a punching machine with a 29φ punching die. In order to calculate the average value of the measurement results of the sound absorption coefficient, five such blocks are prepared.

As a measuring device for the sound absorption coefficient, use the Acoustic Duct/Transfer Function Method Vertical Incidence Acoustic Measurement System Model 9301 manufactured by Rion Co., Ltd., or a device with an equivalent function. The normal incidence acoustic measurement system is a system for measuring the sound absorption coefficient of the material, acoustic impedance related items, and , the transmission loss can be measured. Start up the normal incidence acoustic measurement system, calibrate the microphone, and complete preparations for sound absorption measurement.

　The lump is set at a predetermined position inside the duct so that the sound is incident along the direction parallel to the thickness direction of the lump, and the sound absorption coefficient is measured. The sound absorption coefficient is measured according to JIS A 1405:1994. When the lump has a design surface, the lump is set so that the sound is incident on the design surface.

Then, the normal incident sound absorption coefficients are measured at frequencies of 500 Hz, 630 Hz, 800 Hz, 1000 Hz, 1250 Hz, 1600 Hz, 2000 Hz, 2500 Hz, 3150 Hz, 4000 Hz, 5000 Hz and 6300 Hz. By performing this measurement for each of the five lumps and calculating the average value of the normal incidence sound absorption coefficient at each frequency, the normal incidence sound absorption coefficient at each frequency can be determined. Based on the measurement results, a line graph can be created in which the horizontal axis indicates frequency (Hz) and the vertical axis indicates sound absorption coefficient (%). In the specification of the present application, the line graph is called a "sound absorption coefficient graph". The sound absorption coefficient graphs shown in FIGS. 8 to 11, which will be described later, are logarithmic graphs.

In the above measurement, when the sound absorption coefficient at all frequencies of 1000 Hz, 1250 Hz, 1600 Hz, 2000 Hz, 2500 Hz and 3150 Hz is 40% or more, the normal incidence sound absorption coefficient is 40% or more in the entire frequency range of 1000 Hz to 3150 Hz. can be assumed to exist.

The shape and dimensions of the polyisocyanurate foam according to the embodiment are not particularly limited. An example of the shape of polyisocyanurate foam will be described with reference to FIGS. 1 to 3. FIG.

FIG. 1 is a plan view schematically showing an example of polyisocyanurate foam. In FIG. 1, the case where the polyisocyanurate foam is used as a lower leg impact absorbing material (foot panel) is illustrated as an example. FIG. 2 is a schematic cross-sectional view of the polyisocyanurate foam shown in FIG. 1 taken along line II--II. FIG. 3 is a schematic cross-sectional view of the polyisocyanurate foam shown in FIG. 1 taken along line III--III.

The lower leg shock absorbing material 10 includes a first portion 1, a second portion 2, and a thick portion 3. The first part 1 , the second part 2 and the thick part 3 are integrally formed by molding using one mold to form the lower leg shock absorbing material 10 . The lower leg shock absorber 10 can be mounted, for example, on the floor of an automobile. A floor mat, for example, is laid on the leg shock absorbing material 10 mounted on the floor of an automobile, and both feet of the occupant are placed on the leg shock absorbing material via the floor mat.

The first portion 1 and the second portion 2 are thinner than the thick portion 3. The second portion 2 has a substantially rectangular parallelepiped shape and has an end surface defined by a boundary portion 4 . The first portion 1 and the thick portion 3 extend from the end face of the second portion 2 . The lower leg shock absorbing material 10 is curved so that the boundary portion 4 between the second portion 2 and the first portion 1 and the thick portion 3 forms a valley. The boundary portion 4 forms a trough on one side of the lower leg shock absorbing material 10 and forms a peak on the other side.

The lower leg shock absorbing material 10 has a surface 5 in which the second portion 2, the first portion 1 and the thick portion 3 form a valley. The lower leg shock absorbing material 10 has the second portion 2 and the back surface 6 where the first portion 1 and the thick portion 3 form a peak. The thick portion 3 has a convex shape on the surface 5 . That is, the thick portion 3 has a structure in which the surface 5 protrudes from the surface of the first portion 1 on the basis of the surface of the first portion 1 .

1 to 3 illustrate the case where the polyisocyanurate foam is used as a shock absorbing material for lower limbs, but the use of the polyisocyanurate foam is not particularly limited, and uses that require buckling property and sound absorption performance. is preferably used for Polyisocyanurate foam can be used for door interior cushioning materials, head protection materials, floor raising materials, tool boxes, luggage boxes, ceiling materials, seat core materials, sun visor core materials, pillar core materials, etc. can be done. A polyisocyanurate foam having a desired shape can be obtained by cutting the foam.

[Example]
Examples are described below, but embodiments are not limited to the examples described below.

According to the formulations shown in Tables 1 and 2 below, polyisocyanurate foams according to Examples 1 to 34 were produced by molding. In the table, the mixing ratio of each raw material is shown in parts by weight. However, the "isocyanate index" is the active hydroxyl group equivalent (concentration) in the polyol, materials containing other active hydroxyl group equivalents (concentration), and the isocyanate group equivalent in the polyisocyanate with respect to the sum of the hydroxyl group equivalents (concentration) of water ( concentration).

The details of the "raw material names" listed in Tables 1 and 2 are as follows.

(1) QB8000: manufactured by Toho Chemical Industry Co., Ltd. (weight average molecular weight 8000, polyoxyethylene content 80% by weight, hydroxyl value 28)
(2) T-3000S: Mitsui Chemicals SKC Polyurethane Co., Ltd. (weight average molecular weight 3000, polyoxyethylene content 0% by weight, hydroxyl value 56)
(3) V8010G: manufactured by Dow Chemical (weight average molecular weight 3000, polyoxyethylene content 9% by weight, hydroxyl value 56)
(4) EP-901P: manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd. (weight average molecular weight 7000, polyoxyethylene content 15% by weight, hydroxyl value 23)
(5) CP1421: manufactured by Dow Chemical (weight average molecular weight 5000, polyoxyethylene content 75% by weight, hydroxyl value 33.5)
(6) FA166: manufactured by Sanyo Chemical Industries, Ltd. (weight average molecular weight 6700, polyoxyethylene content 70% by weight, hydroxyl value 25)
(7) T-5000D: manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd. (weight average molecular weight 5000, polyoxyethylene content 0% by weight, hydroxyl value 33.7)
(8) V4701: manufactured by Dow Chemical (weight average molecular weight 5000, polyoxyethylene content 10% to 12% by weight, hydroxyl value 33.7)
(9) KC745: manufactured by Sanyo Chemical Industries, Ltd. (weight average molecular weight 5000, polyoxyethylene content 20% to 25% by weight, hydroxyl value 33.7)
(10) EP-505S: manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd. (weight average molecular weight 3000, polyoxyethylene content 70% to 75% by weight, hydroxyl value 51)
(11) JEFFCAT DPA: Huntsman Japan Co., Ltd. Substance name: 1,1'-[[3-(dimethylamino)propyl]imino]bis(2-propanol)
Application: Resin catalyst (12) TMR7: Air Products Japan Co., Ltd. Application: Trimerization catalyst (13) DEA: Diethanolamine
Application: Surface modification catalyst (14) NE300: Manufactured by Evonik Japan KK Application: Foaming catalyst (15) Niax catalyst A-1: Manufactured by Momentive Performance Materials, Inc. Application: Foaming catalyst (16) B8228 : Evonik Japan Co., Ltd. (17) EM ALEX DEG-di-O: Nippon Emulsion Co., Ltd. Substance name: Diethyl glycol dioleate (18) SF2962: Dow Corning Toray Co., Ltd. (19) VORASURF 1280: Toray Co., Ltd. Dow Corning Co., Ltd. (20) Irganox 1135: BASF Japan Co., Ltd. Application: Antioxidant (21) Sumidur 44 V 20 L: Sumika Covestro Urethane Co., Ltd.

(Example 1)
A polyol-containing mixture was prepared in a disposable cup by blending the raw materials other than the polyisocyanate, ie, the polyol component, additives, catalyst and blowing agent, according to the formulation shown in Table 1 (by hand foaming). The polyol component according to Example 1 includes QB8000 corresponding to polyol A and T-3000S corresponding to polyol B. Let the obtained polyol containing mixture be A liquid. The temperature of liquid A was adjusted to 37°C ± 2°C. Also, a polyisocyanate was prepared as the B liquid, and the temperature of the B liquid was adjusted to 37°C ± 2°C.

A sample-making mold with internal dimensions of 350 mm in width, 350 mm in depth, and 70 mm in height is prepared, and the mold is heated to a temperature range of 65°C to 70°C to maintain the temperature. The temperature was measured using a surface thermometer. The mold consists of a cylindrical lower mold with a bottom that is open only at the top, and an upper mold that can close the top.

Next, B liquid was added to A liquid prepared in the disposable cup, and the mixture was stirred and mixed for 5 seconds to obtain a mixed solution. Here, when the total weight part of the polyol component is 100, the weight part of the A liquid containing the said polyol component was 120.5 weight part, and the weight part of the B liquid was 77.3 weight part. The resulting mixed solution was immediately put into the lower mold, and the upper surface of the lower mold was closed with the upper mold to cure for 6 minutes. During this time, the surface temperature of the mold is maintained at 65.degree. C. to 70.degree. Thereafter, the mold was removed from the mold and allowed to stand at room temperature for 2 days to obtain a polyisocyanurate foam having dimensions of 350 mm×350 mm×70 mm.

(Examples 2-9)
A polyisocyanurate foam was obtained in the same manner as in Example 1, except that the isocyanate index was changed as shown in Table 1 by changing the amount of polyisocyanate in the formulation as shown in Table 1. rice field.

(Examples 10-20)
A polyisocyanurate foam was obtained in the same manner as in Example 1, except that the mixing ratio of QB8000 corresponding to polyol A and T-3000S corresponding to polyol B was changed as shown in Table 1.

(Examples 21-26)
A polyisocyanurate foam was obtained in the same manner as in Example 1, except that the type and blending amount of the polyol used were changed as shown in Table 2.

(Examples 27-33)
A polyisocyanurate foam was obtained in the same manner as in Example 1, except that the types of polyols and foam stabilizers used and their blending amounts were changed as shown in Table 2.

(Example 34)
A polyisocyanurate foam was obtained in the same manner as in Example 1, except that the formulation of liquid A was changed as shown in Table 2 and the isocyanate index was changed to 150.

<Moldability evaluation>
The moldability (curability) of the polyisocyanurate foam according to each example was evaluated by sensory evaluation. "○" indicates that the foam is in good condition at the time of demolding, and "△" indicates that the cell structure is rough or that the foam is missing, and the polyisocyanurate foam is collapsed or severe. The case where the cure was insufficient was evaluated as "x". Examples of the breakdown of the evaluation "x" include, for example, when demolding is attempted, strings are drawn, the foam is ragged and brittle, or the cells inside the foam are collapsed and depressed.

<Hysteresis loss rate measurement>
For the polyisocyanurate foam according to each example, the hysteresis loss rate (%) was measured according to the method described in the embodiment. A sample with a hysteresis loss rate of 90% or more was rated as "good", and a sample with a hysteresis loss rate of less than 90% was rated as "x". However, the hysteresis loss ratio was not measured for those with an evaluation of "x" in the moldability evaluation, because the hysteresis loss rate could not be measured appropriately. In the row of "hysteresis loss rate" in Tables 1 and 2, "-" indicates an example in which measurement was not performed.

<Sound absorption performance evaluation>
The sound absorption performance of the polyisocyanurate foam according to each example was evaluated according to the method for measuring the normal incidence sound absorption coefficient described in the embodiment. Those with a normal incidence sound absorption coefficient of 40% or more in the entire frequency range of 1000Hz to 3150Hz are marked with "○", and those with a band with a normal incidence sound absorption coefficient of less than 40% in the frequency range of 1000Hz to 3150Hz with "○". x” was evaluated. However, in the evaluation of formability, evaluation was not carried out for those evaluated as "x" because the sound absorption performance could not be evaluated appropriately. In the row of "sound absorption performance" in Tables 1 and 2, examples that were not evaluated are indicated by "-".

<Density measurement>
The density of the polyisocyanurate foam according to each example was measured and found to be 60 kg/m ³ in all cases. Density was evaluated according to the measurement method specified in JIS K 7222:2005.

As shown in Tables 1 and 2, the polyisocyanurate foams according to Examples 1 to 9, Examples 14 to 22, and Examples 26 to 34 had practical moldability. In other words, since these examples were evaluated for moldability as "good" or "fair", it was possible to perform various evaluations.

Figures 4-8 show the stress/displacement curves for each example. In the stress/displacement curves shown in FIGS. 4 to 8, the horizontal axis indicates displacement (%) and the vertical axis indicates stress (kgf/cm ² ). A hysteresis loss rate was calculated from the obtained stress/displacement curve. 9 to 13 are sound absorption coefficient graphs showing the results of normal incidence sound absorption coefficient measurements for each example. In the sound absorption coefficient graph, the horizontal axis indicates frequency (Hz) and the vertical axis indicates sound absorption coefficient (%).

FIG. 4 shows the stress/displacement curves for Examples 1 to 9 with different isocyanate indexes. As the isocyanate index increases, the nurate structure increases, so it can be seen that the polyisocyanurate foam tends to harden. In particular, in Examples 4 to 6, the stress at the time of return was small, and the impact absorption performance was high. FIG. 9 shows sound absorption coefficient graphs according to Examples 1 to 9. In FIG. The polyisocyanurate foams according to Examples 1 to 6 achieved sound absorption coefficients of 40% or more over the entire range of 1000 Hz to 3150 Hz. In Examples 1 to 6, since the content of the nurate structure was appropriate, the communication was also appropriate, and the sound absorbing performance aimed at by the present invention was achieved. In Examples 7 to 9, the cell structure was rough and the communication was excessive, so it is considered that they were out of the range of the predetermined sound absorption performance.

FIG. 5 shows stress/displacement curves for Examples 14 to 20. Examples 14 to 20 show the results when the weight ratio of polyol A to polyol B is gradually changed. Examples with a low ratio of polyol A tended to have a low hysteresis loss rate. Examples 17 to 20 with a hysteresis loss rate exceeding 90% are found to be excellent in shock absorption performance. Also, FIG. 10 shows a sound absorption coefficient graph according to Examples 14 to 20. In FIG. The polyisocyanurate foams according to Examples 15 to 18 achieved a sound absorption coefficient of 40% or more over the entire range of 1000Hz to 3150Hz. Examples 17 and 18, in which the number of parts of polyol A in the polyol component was in the range of 70 parts by weight to 80 parts by weight, showed excellent sound absorption even in the low frequency range.

Fig. 6 shows stress/displacement curves for examples in which the type of polyol used as the polyol component is changed. The polyisocyanurate foams according to Examples 4, 21, 22 and 26, which were obtained from reaction systems containing polyol A and polyol B that satisfy a predetermined weight average molecular weight and ethylene oxide content, were excellent in moldability. , the hysteresis loss rate was also 90% or more. Also, FIG. 11 shows a sound absorption coefficient graph according to Examples 21, 22 and 26. In FIG. All examples are examples containing polyol A and polyol B that satisfy the predetermined weight average molecular weight and ethylene oxide content, so they achieve a sound absorption coefficient of 40% or more not only in the range of 1000 Hz to 3150 Hz but also in a wide frequency range. did.

Fig. 7 shows stress/displacement curves for examples in which the type of polyol used as the polyol component is changed. The polyisocyanurate foams according to Examples 4, 27, 28, 30, 31 and 33 obtained by a reaction system comprising Polyol A and Polyol B satisfying a given weight average molecular weight and ethylene oxide content, The moldability was excellent, and the hysteresis loss rate was 90% or more. 12 shows sound absorption coefficient graphs according to Examples 4, 27, 28, 30, 31 and 33. In FIG. All examples are examples containing polyol A and polyol B that satisfy the predetermined weight average molecular weight and ethylene oxide content, so they achieve a sound absorption coefficient of 40% or more not only in the range of 1000 Hz to 3150 Hz but also in a wide frequency range. did.

FIG. 8 shows the stress/displacement curve according to Example 34. Also, FIG. 13 shows a sound absorption coefficient graph according to Example 34. As shown in FIG. From Example 34, for example, the following can be read. That is, even when using a polyol component containing polyol A and polyol B that satisfy a predetermined weight average molecular weight and ethylene oxide content, the isocyanate index is low and/or the type of other components included in the reaction system And if the number of copies is not properly controlled, the hysteresis loss rate will be less than 90%. However, as shown in FIG. 13, the polyisocyanurate foam according to Example 34 achieved a sound absorption coefficient of 40% or more not only within the range of 1000 Hz to 3150 Hz, but also over a wide frequency range.

It should be noted that the present invention is not limited to the above-described embodiments, and can be variously modified in the implementation stage without departing from the gist of the present invention. Further, each embodiment may be implemented in combination as appropriate, in which case the combined effect can be obtained. Furthermore, various inventions are included in the above embodiments, and various inventions can be extracted by combinations selected from a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, if the problem can be solved and effects can be obtained, the configuration with the constituent elements deleted can be extracted as an invention.

1... First part, 2... Second part, 3... Thick part, 4... Boundary part, 5... Front surface, 6... Back surface, 10... Impact absorbing material for lower limbs.

Claims

A polyisocyanurate foam obtained by foaming in a reaction system containing a polyol, a polyisocyanate, a foam stabilizer, a catalyst and a blowing agent,
The polyols are polyol A having a weight average molecular weight in the range of 3000 to 12000 and an ethylene oxide content of 50% by weight or more, and polyol A having a weight average molecular weight of 1000 to 8000 and an ethylene oxide content of less than 20% by weight. and a polyol B,
The isocyanate index in the reaction system is 200 or more and 350 or less,
The hysteresis loss rate is 90% or more,
The hysteresis loss rate is
cutting a measurement sample having dimensions of 50 mm×50 mm×50 mm from the polyisocyanurate foam;
Compressing the measurement sample along the foaming height direction of the polyisocyanurate foam to a reference thickness at which a load of 5 N is applied using an 80φ compressor;
Immediately after compressing the measurement sample along the foam height direction at a speed of 50 mm / min until the thickness displacement from the reference thickness reaches 70%, the thickness displacement from the reference thickness is 0. and returning the measurement sample along the foam height direction at a speed of 50 mm/min until the polyisocyanurate foam reaches %.
The polyisocyanurate foam according to claim 1, wherein the weight ratio of said polyol A to the weight of said polyol is in the range of 65% by weight to 85% by weight.
The polyisocyanurate foam according to claim 1 or 2, wherein the weight ratio of the polyol B to the weight of the polyol is in the range of 15% by weight to 35% by weight.
The polyisocyanurate foam according to any one of claims 1 to 3, wherein the polyol A has a weight average molecular weight in the range of 3,000 to 9,000.
The polyisocyanurate foam according to any one of claims 1 to 4, wherein the foam stabilizer is a silicone foam stabilizer.
The polyisocyanurate foam according to any one of claims 1 to 5, wherein the foaming agent is water.
The polyisocyanurate foam according to any one of claims 1 to 6, wherein the reaction system comprises only the polyol, the polyisocyanate, the foam stabilizer, the blowing agent and the catalyst.