Polyurethane foam and printer roller

Abstract

To provide a polyurethane foam that exhibits high conductivity even with reduced content of PFAS, and a printer roller using the same.SOLUTION: A polyurethane foam is produced by the reaction and foaming of a raw material mixture containing a polyol component, a polyisocyanate component, a blowing agent, and an ionic compound. The ionic compound includes a quaternary ammonium salt represented by the following formula (1) (where R1, R2, and R3 are each an alkyl group having 1 to 18 carbon atoms; n is an integer of 1 or more; and X- is a monovalent anion). A printer roller includes such a polyurethane foam.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyurethane foam and a printer roller, and more particularly to a polyurethane foam having a low volume resistivity and an appropriate hardness, and a printer roller using the same.

Background Art

[0002] Polyurethane refers to a polymer compound having a urethane bond (-NH-C(O)O-). Polyurethane is obtained by reacting the hydroxyl group (-OH) of a polyol with the isocyanate group (-NCO) of a polyisocyanate. It is known that polyurethane exhibits various properties by optimizing the types of polyol and / or polyisocyanate. Therefore, polyurethane is applied to various automotive parts, synthetic leather, paints, adhesives, etc. In addition, polyurethane foam obtained by foaming polyurethane is applied to heat insulating materials, cushioning materials, etc.

[0003] Polyurethane foam usually has a high volume resistivity. Therefore, a conductive agent is added to the polyurethane foam used for applications where conductivity is required. The conductive agent may be added in advance to the raw materials for synthesizing the polyurethane foam, or may be added later to the synthesized polyurethane foam. In addition, the conductive agent may be chemically bonded to the polymer chain of the polyurethane foam or physically entangled with the polymer chain.

[0004] Regarding such a polyurethane foam having conductivity, various proposals have been made conventionally. For example, in Patent Document 1, (a) Polyether polyol (weight average molecular weight: 3000, functionality: 3, hydroxyl value 56 mgKOH / g): 100 parts by mass, (b) Potassium bis(trifluoromethanesulfonyl)imide: 2 parts by mass, (c) Foaming agent (water): 4.7 parts by mass, (d) Amine catalyst: 0.1 part by mass, (e) Blowing agent: 0.83 parts by mass, (f) Metal catalyst: 0.19 parts by mass, and (g) Polyisocyanate (mixture of 80% 2,4-TDI and 20% 2,6-TDI): 57 parts by mass A polyurethane foam obtained by reacting and foaming is disclosed. In the same document, it is described that a polyurethane foam having a volume resistivity of 6.7×10 9 Ω·cm can be obtained by such a method.

[0005] As described in Patent Document 1, when a certain ionic compound is added to a polyurethane foam, conductivity can be imparted to the polyurethane foam. However, the ionic compound used in Patent Document 1 is a kind of PFAS (perfluoroalkyl compound and polyfluoroalkyl compound).

[0006] PFAS is defined as a fluoride containing at least one fully fluorinated methyl group or methylene carbon atom. Since PFAS is extremely stable and hardly decomposable, it is considered to remain in the environment for a long time if the discharge to the environment continues. In addition, PFAS remaining in the environment is considered to possibly affect human health and the survival and growth of animals and plants through the food chain. Therefore, the use of PFAS may be restricted in the future, and a polyurethane foam showing high conductivity without using PFAS is desired.

[0007] Also, when manufacturing a conductive polyurethane foam, if a certain ionic compound is added to the raw materials, the hardness of the polyurethane foam may decrease. This is presumably because the OH groups contained in the polyol react with the ionic compound, reducing the crosslinking degree of the polyurethane foam. However, there has been no prior example of a polyurethane foam that has high conductivity despite having a low PFAS content and has an appropriate hardness.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] The problem to be solved by the present invention is to provide a polyurethane foam that exhibits high conductivity even when the PFAS content is low. Another problem to be solved by the present invention is to provide a polyurethane foam that has an appropriate hardness in addition to high conductivity and low PFAS content. Furthermore, another problem to be solved by the present invention is to provide a printer roller provided with such a polyurethane foam.

Means for Solving the Problems

[0010] To solve the above problems, the polyurethane foam according to the present invention is obtained by reacting and foaming a raw material mixture containing a polyol component, a polyisocyanate component, a foaming agent, and an ionic compound, wherein the ionic compound contains a quaternary ammonium salt represented by the following formula (1).

[0011] The polyol component may contain a polymeric polyol. In addition to or instead of this, the raw material mixture may further contain a crosslinking agent.

[0012] The printer roller according to the present invention includes the polyurethane foam according to the present invention.

Advantages of the Invention

[0013] When a quaternary ammonium salt having a specific molecular structure is added to a raw material mixture for producing a polyurethane foam, a polyurethane foam exhibiting high conductivity can be obtained even when the content of PFAS is low. This is considered to be because charges move through the cations and / or anions constituting the quaternary ammonium salt.

[0014] In addition, when a quaternary ammonium salt is added to the raw material mixture, the hardness of the polyurethane foam may decrease. On the other hand, when a polymeric polyol is used as the polyol component and / or a crosslinking agent is added to the raw material mixture, the decrease in hardness caused by the addition of the quaternary ammonium salt can be suppressed.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, an embodiment of the present invention will be described in detail. [1. Polyurethane Foam] The polyurethane foam according to the present invention is a polyol component, a polyisocyanate component, a foaming agent, and an ionic compound and is obtained by reacting and foaming a raw material mixture containing the same. The raw material mixture usually further contains a foam stabilizer and a catalyst. The raw material mixture may further contain other additives as necessary.

[0016] [1.1. Components] [1.1.1. Polyol Component] The raw material mixture contains a polyol component. The polyol component may contain only one type of polyol, or may contain two or more types of polyols. In the present invention, the “polyol” contained in the polyol component refers to a polyol having 2 or more functional groups and a molecular weight exceeding 500.

[0017] The polyol may be (a) a polyether polyol obtained by addition polymerization of an alkylene oxide to an initiator, (b) a polyester polyol obtained by dehydration condensation of a carboxylic acid and a polyhydric alcohol, (c) a polymer polyol in which polymer fine particles obtained by copolymerizing acrylonitrile or styrene are dispersed in a polyether polyol any of them. In order to suppress the decrease in hardness caused by the quaternary ammonium salt, the polyol component preferably contains a polymer polyol.

[0018] [B. Weight-average molecular weight] In the present invention, the weight-average molecular weight of the polyol component is not particularly limited, and an optimum value can be selected according to the purpose. Generally, if the weight-average molecular weight of the polyol component is too small, the hardness of the polyurethane foam may become excessively high. Therefore, the weight-average molecular weight of the polyol component needs to be more than 500. The weight-average molecular weight is more preferably 1000 or more, 1500 or more, or 2000 or more. On the other hand, if the weight-average molecular weight of the polyol component is too large, the polyurethane foam becomes difficult to melt and the processability may decrease. Therefore, the weight-average molecular weight of the polyol component is preferably 10000 or less. The weight-average molecular weight is more preferably 9000 or less, 8000 or less, 7000 or less, or 6000 or less.

[0019] [C. Average functionality] In the present invention, the average functionality of the polyol component is not particularly limited, and an optimum value can be selected according to the purpose. Generally, the higher the average functionality of the polyol component, the higher the hardness of the polyurethane foam. The average functionality of the polyol component may be 2.0 or more. The average functionality is more preferably 2.3 or more, 2.5 or more, or 2.7 or more. On the other hand, when the average functionality of the polyol component becomes excessive, the hardness of the polyurethane foam may become excessively high. Therefore, the average functionality of the polyol component is preferably 4.0 or less. More preferably, the average functionality is 3.8 or less, 3.6 or less, or 3.4 or less.

[0020] [D. Average hydroxyl value] In the present invention, the average hydroxyl value of the polyol component is not particularly limited, and an optimum value can be selected according to the purpose. Generally, when the average hydroxyl value of the polyol component becomes too small, the processability of the polyurethane foam may decrease, or the hardness of the polyurethane foam may decrease excessively. Therefore, the average hydroxyl value of the polyol component is preferably 12.0 mgKOH / g or more. More preferably, the average hydroxyl value is 15.0 mg / g or more, 20.0 mgKOH / g or more, or 25.0 mgKOH / g or more. On the other hand, when the average hydroxyl value of the polyol component becomes too large, the hardness of the polyurethane foam may become excessively high. Therefore, the average hydroxyl value of the polyol component is preferably 400.0 mgKOH / g or less. More preferably, the average hydroxyl value is 300.0 mgKOH / g or less, 200.0 mgKOH / g or less, or 100.0 mgKOH / g or less.

[0021] [E. EO content] The "EO content" refers to the ratio of the mass of ethylene oxide (EO) units to the total mass of alkylene oxide units contained in the polyether polyol. When the polyether polyol contains alkylene oxide units other than EO units, the alkylene oxide units other than EO units are not particularly limited, but propylene oxide (PO) units are preferred.

[0022] When using a polyether polyol as the polyol, the EO content of the polyether polyol is not particularly limited, and an optimum value can be selected according to the purpose.

[0023] [1.1.2. Polyisocyanate Component] The raw material mixture contains a polyisocyanate component. The polyisocyanate component may contain one type of polyisocyanate or may contain two or more types of polyisocyanates. Also, the functionality of the polyisocyanate is not particularly limited, and an optimal functionality can be selected according to the purpose.

[0024] Examples of polyisocyanates include (a) aromatic isocyanate compounds, aliphatic isocyanate compounds, or alicyclic isocyanate compounds, (b) modified products of the above compounds and the like.

[0025] Examples of aromatic isocyanate compounds include, for example, diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate, tolylene diisocyanate (TDI), naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), xylene diisocyanate (XDI), tetramethylxylene diisocyanate (TMXDI), toluidine diisocyanate (TODI), and the like.

[0026] Examples of aliphatic isocyanate compounds include, for example, hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), lysine triisocyanate (LTI), and the like.

[0027] Examples of alicyclic isocyanate compounds include, for example, isophorone diisocyanate (IPDI), cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H6XDI), Hydrogenated MDI (H 12 MDI), etc. may be mentioned.

[0028] Examples of the modified isocyanate compound include urethane-modified products, dimers, trimers, carbodiimide-modified products, allophanate-modified products, burette-modified products, urea-modified products, isocyanurate-modified products, oxazolidone-modified products, isocyanate group-terminated prepolymers, etc. of the isocyanate compound.

[0029] [1.1.3. Blowing agent] The raw material mixture contains a blowing agent. The "blowing agent" refers to an additive for generating bubbles in the raw material mixture during the process of resinification of the liquid raw material mixture. In the present invention, the blowing agent is (a) a physical blowing agent that generates gas by pressure reduction or heating, or (b) a chemical blowing agent that generates gas by thermal decomposition or chemical reaction may be either of them.

[0030] Examples of the physical blowing agent include (a-1) hydrocarbons such as cyclopentane, isopentane, and normal pentane, (a-2) halogen-based compounds such as methylene chloride, trichlorofluoromethane, dichlorodifluoromethane, nonafluorobutyl methyl ether, pentafluoroethyl methyl ether, and pentafluoroisopropyl methyl ether, and the like.

[0031] Examples of the chemical blowing agent include (b-1) water that reacts with an isocyanate group to generate CO2, (b-2) azodicarbonamide that generates nitrogen, carbon monoxide, carbon dioxide, or ammonia gas by thermal decomposition and the like.

[0032] The raw material mixture may contain any one of these blowing agents, or may contain two or more of them. Among these, water is preferred as the blowing agent. When water is used as the blowing agent, the CO2 gas generated by the reaction of water and isocyanate groups promotes foaming. In addition, the heat of reaction between water and isocyanate groups promotes the curing of the resin.

[0033] [1.1.4. Ionic Compound] [A. Quaternary Ammonium Salt] The raw material mixture contains an ionic compound. In the present invention, the raw material mixture contains, as the ionic compound, a quaternary ammonium salt represented by the following formula (1). The quaternary ammonium salt represented by the formula (1) is an ionic compound having an OH group. When this is added to the raw material mixture and reacted, the OH group of the quaternary ammonium salt reacts with the NCO group of the polyisocyanate, and the quaternary ammonium cation binds to the polymer chain. As a result, the obtained polyurethane foam exhibits high conductivity.

[0034] [Chemical Formula]

[0035] However, R1, R2, and R3 are each an alkyl group having 1 or more and 18 or less carbon atoms, n is an integer of 1 or more, X - is a monovalent anion.

[0036] In the formula (1), R1, R2, and R3 each represent a functional group bonded to the nitrogen atom. In the present invention, R1, R2, and R3 each consist of an alkyl group having 1 or more and 18 or less carbon atoms. Examples of R1, R2, and R3 include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, an amyl group, a hexyl group, a heptyl group, an n-octyl group, an isooctyl group, a 2-ethylhexyl group, a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, and the like. Among these, R1 is a dodecyl group (-C 12 H 25) is preferred. Further, each of R2 and R3 preferably represents a methyl group (-CH3).

[0037] In formula (1), n represents the number of repetitions of the -O-CH2CH2- unit. In the present invention, n may be an integer of 1 or more. However, if n becomes too large, the fluidity of the raw material mixture may decrease, making it difficult to handle. Therefore, n is preferably 10 or less.

[0038] In formula (1), X - represents a monovalent anion. In the present invention, the type of X - is not particularly limited, and an optimal one can be selected according to the purpose. Examples of X - include, for example, perchlorate anion, halogen anion, thiocyanate anion, methyl sulfate anion, sulfonate anion (e.g., tosylate anion, triflate anion, mesylate anion, etc.), tetrafluoroborate anion (BF 4- ), hexafluorophosphate anion (PF 6- ), tetrakis(pentafluorophenyl)borate anion (B(C6F5) 4- ), sulfate anion, nitrate anion, nitrite anion, sulfite anion, carboxylate anion, etc. Among these, X - is preferably perchlorate anion.

[0039] [B. Other Ionic Compounds] In addition to the quaternary ammonium salt, the raw material mixture may further contain a bissulfonylimide salt represented by the following formula (2) and / or a hexafluorophosphate salt represented by the following formula (3) as ionic compounds. When the raw material mixture further contains a bissulfonylimide salt and / or a hexafluorophosphate salt, the conductivity of the polyurethane foam may be further increased compared to the case where only the quaternary ammonium salt is contained.

[0040] [Chemical Formula]

[0041] However, R4 and R5 are each (a) a fluorine atom, or (b) a saturated or unsaturated linear or branched alkyl group having 1 to 10 carbon atoms in which part or all of the hydrogen atoms are substituted with fluorine atoms Z1 + and Z2 + are each a monovalent cation.

[0042] In formula (2), R4 and R5 each represent a functional group bonded to a sulfonyl group (-SO2-). In the present invention, R4 and R5 each consist of a fluorine atom, a perfluoroalkyl group, or a hydrofluoroalkyl group. Examples of R4 and R5 include -F, -CF3, -CHF2, -C2F5, and the like. Among these, -CF3 is preferable for each of R4 and R5.

[0043] In formula (2) and formula (3), Z1 + , and Z2 + each represent a monovalent cation. In the present invention, the types of Z1 + , and Z2 + are not particularly limited, and the most suitable ones can be selected according to the purpose. Z1 + , and Z2 + include, for example, (a) an onium cation of a 5- or 6-membered ring compound having 1 to 3 nitrogen atoms, (b) a quaternary ammonium cation, (c) a phosphonium cation, (d) an alkali metal cation and the like.

[0044] Examples of the onium cation of a 5-membered ring compound having 1 to 3 nitrogen atoms include an imidazolium cation and a pyrrolidinium cation. Examples of the onium cations of the six-membered ring compound having 1 to 3 nitrogen atoms include pyridinium cation and piperidinium cation. Among these, Z1 + , and Z2 + are preferably an imidazolium cation or a pyridinium cation, respectively.

[0045] [1.1.5. Crosslinking agent] In addition to the above-described components, the raw material mixture may further contain a crosslinking agent. In the present invention, the "crosslinking agent" refers to an organic compound having 3 or more active hydrogen groups in one molecule and a molecular weight of 500 or less. Examples of the active hydrogen group include -OH, -NH2, -SH, -NRH (R is an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or an acyl group). When producing a polyurethane foam from a raw material mixture containing a quaternary ammonium salt, the hardness of the polyurethane foam may decrease. In such a case, when a crosslinking agent is added to the raw material mixture, a decrease in the hardness of the polyurethane foam can be suppressed.

[0046] In the present invention, the type of the crosslinking agent is not particularly limited, and an optimal one can be selected according to the purpose. Examples of the crosslinking agent include ethylenediamine-based polyether polyol, trimethylolpropane-based polyether polyol, glycerin-based polyether polyol, pentaerythritol-based polyether polyol, dipentaerythritol-based polyether polyol, sorbitol-based polyether polyol, and the like.

[0047] [1.1.6. Catalyst] The raw material mixture usually contains a catalyst. The "catalyst" refers to a catalyst having a great effect of promoting the resinification reaction, a catalyst having a great effect of promoting the foaming reaction (reaction between an isocyanate group and water), or a catalyst having an effect of promoting both the resinification reaction and the foaming reaction. In the present invention, the type of the catalyst is not particularly limited, and an optimal catalyst can be selected according to the purpose.

[0048] Examples of the catalyst include amine catalysts, metal catalysts, etc. An amine catalyst is a catalyst that promotes both the resinification reaction and the foaming reaction. A metal catalyst is a catalyst that has a great effect of promoting the resinification reaction. The raw material mixture may contain any one of these catalysts, or may contain two or more of them.

[0049] Examples of the amine catalyst include N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine, N,N-dimethylaminoethanol, N,N-dimethylaminohexanol, N,N’,N’-trimethylaminoethylpiperazine, triethylenediamine and the like.

[0050] Examples of the metal catalyst include (a) Tin catalysts such as stannous octoate and dibutyltin dilaurate, (b) Mercury catalysts such as phenylmercury propionate, (c) Lead catalysts such as lead octenoate and the like.

[0051] [1.1.7. Foam stabilizer] The raw material mixture usually contains a foam stabilizer. The "foam stabilizer" refers to an additive that has the effect of making the size and distribution of bubbles uniform. When a foam stabilizer is added to the raw material mixture, a polyurethane foam with uniform bubble size and distribution can be obtained. Examples of the foam stabilizer include silicone-based foam stabilizers, fluorine-containing compound-based foam stabilizers, known surfactants, etc.

[0052] [1.2. Content] [1.2.1. Content of polymer polyol] The "content of polymer polyol" refers to the mass of polymer polyol contained in the polyol component (that is, the ratio of the mass of polymer polyol to the total mass of the polyol component) when the total mass of the polyol component is 100.

[0053] In the present invention, the content of the polymer polyol may be 0 parts by mass. However, when producing a polyurethane foam from a raw material mixture containing a quaternary ammonium salt, the hardness of the polyurethane foam may decrease. In such a case, adding a polymer polyol to the raw material mixture can suppress the decrease in hardness caused by the quaternary ammonium salt. To obtain such an effect, the content of the polymer polyol is preferably 10 parts by mass or more. The content is more preferably 20 parts by mass or more, or 30 parts by mass or more. On the other hand, when the content of the polymer polyol becomes excessive, the electrical resistivity may increase excessively. Therefore, the content of the polymer polyol is preferably 90 parts by mass or less. The content is more preferably 80 parts by mass or less, 60 parts by mass or less, or 50 parts by mass or less. Particularly preferred contents of the polymer polyol are 10 to 90 parts by mass, 20 to 80 parts by mass, or 30 to 50 parts by mass.

[0054] [1.2.2. Content of Quaternary Ammonium Salt] The "content of the quaternary ammonium salt" refers to the mass of the quaternary ammonium salt when the total mass of the polyol component is 100.

[0055] If the content of the quaternary ammonium salt becomes too low, the volume resistivity of the polyurethane foam may become excessively large. Therefore, the content of the quaternary ammonium salt is preferably 0.5 parts by mass or more. The content is more preferably 1.0 parts by mass or more, 2.0 parts by mass or more, or 3.0 parts by mass or more. On the other hand, when the content of the quaternary ammonium salt becomes excessive, the hardness of the polyurethane foam may decrease. Therefore, the content of the quaternary ammonium salt is preferably 10.0 parts by mass or less. The content is more preferably 9.0 parts by mass or less, or 8.0 parts by mass or less.

[0056] [1.2.3. Total content of bissulfonylimide salt and hexafluorophosphate salt] The "total content of bissulfonylimide salt and hexafluorophosphate salt" refers to the total mass of bissulfonylimide salt and hexafluorophosphate salt when the total mass of the polyol component is 100.

[0057] In the present invention, the total content of bissulfonylimide salt and hexafluorophosphate salt may be 0 parts by mass. However, when these are further added to the raw material mixture, the volume resistivity of the polyurethane foam further decreases. To obtain such an effect, the total content of bissulfonylimide salt and hexafluorophosphate salt is preferably 0.5 parts by mass or more. The total content is more preferably 1.0 parts by mass or more, or 1.5 parts by mass or more. On the other hand, when the total content of bissulfonylimide salt and hexafluorophosphate salt becomes excessive, there may be concerns about the environmental load. Therefore, the total content of bissulfonylimide salt and hexafluorophosphate salt is preferably 5.0 parts by mass or less. The total content is more preferably 4.5 parts by mass or less, or 4.0 parts by mass or less.

[0058] [1.2.4. Content of crosslinking agent] The "content of crosslinking agent" refers to the mass of the crosslinking agent when the total mass of the polyol component is 100.

[0059] In the present invention, the content of the crosslinking agent may be 0 parts by mass. However, when producing a polyurethane foam from a raw material mixture containing a quaternary ammonium salt, the hardness of the polyurethane foam may excessively decrease. In such a case, adding a crosslinking agent to the raw material mixture can suppress the decrease in hardness caused by the quaternary ammonium salt. To obtain such an effect, the content of the crosslinking agent is preferably 0.5 parts by mass or more. The content is more preferably 1.0 parts by mass or more, 1.5 parts by mass or more, or 2.0 parts by mass or more. On the one hand, when the content of the crosslinking agent becomes excessive, the hardness of the polyurethane foam may become excessively high. Therefore, the content of the crosslinking agent is preferably 10.0 parts by mass or less. More preferably, the content is 9.0 parts by mass or less, 8.0 parts by mass or less, 7.0 parts by mass or less, or 6.0 parts by mass or less.

[0060] [1.2.5. Content of Polyisocyanate] The "isocyanate index" refers to the value obtained by multiplying by 100 the ratio of the equivalent of the isocyanate groups of the polyisocyanate in the raw material mixture to the equivalent of the active hydrogen groups in the raw material mixture.

[0061] If the isocyanate index becomes too small, the hardness of the polyurethane foam may decrease excessively. Also, the crosslinking density may decrease excessively, and the foam may not be formed. Therefore, the isocyanate index is preferably 80 or more. More preferably, the isocyanate index is 85 or more, 90 or more, 95 or more, or 100 or more. On the other hand, if the isocyanate index becomes too large, the polyurethane foam may become excessively hard. Also, the heat generation during the reaction may become excessively large, and the polyurethane foam may burn or ignite. Therefore, the isocyanate index is preferably 120 or less. More preferably, the isocyanate index is 119 or less, 118 or less, or 117 or less.

[0062] [1.2.6. Content of Foaming Agent] The "content of the foaming agent" refers to the mass of the foaming agent when the mass of the polyol component is 100. It is preferable to select the optimum content according to the type of the foaming agent.

[0063] For example, when the foaming agent is water, if the content of water becomes too small, the density of the polyurethane foam may become excessively high. Therefore, the content of water is preferably 0.5 parts by mass or more. More preferably, the content is 0.7 parts by mass or more, or 1.0 parts by mass or more. On the one hand, when the water content becomes excessive, the density of the polyurethane foam may decrease excessively. In addition, the heat generation temperature due to the reaction (foaming reaction and resinification reaction) may become excessively high, and scorch (burning, charring) may occur in the polyurethane foam. Therefore, the water content is preferably 1.5 parts by mass or less. More preferably, the content is 1.4 parts by mass or less.

[0064] [1.2.7. Content of catalyst] The "content of catalyst" refers to the mass of the catalyst when the mass of the polyol component is 100. When two or more catalysts are used, the "mass of the catalyst" refers to the total mass of the two or more catalysts.

[0065] When one or more foaming catalysts are included in the raw material mixture, the more the content of the foaming catalyst increases, the more the reaction proceeds in a short time. To obtain such an effect, the content of the foaming catalyst is preferably 0.05 parts by mass or more. More preferably, the content is 0.07 parts by mass or more, or 0.09 parts by mass or more. On the other hand, when the content of the foaming catalyst becomes excessive, the balance between the foaming reaction and the resinification reaction may be disrupted, and the foam may collapse (a phenomenon in which the foam collapses and sinks while rising). Therefore, the content of the foaming catalyst is preferably 0.15 parts by mass or less. More preferably, the content is 1.4 parts by mass or less, or 1.3 parts by mass or less.

[0066] Also, when one or more resinification catalysts are included in the raw material mixture, the more the content of the resinification catalyst increases, the more the reaction proceeds in a short time. To obtain such an effect, the content of the resinification catalyst is preferably 0.20 parts by mass or more. More preferably, the content is 0.21 parts by mass or more, or 0.22 parts by mass or more. On the one hand, when the content of the resinification catalyst becomes excessive, the resin skeleton becomes tough, and the gas generated during the reaction may not escape outside the foam, and the foam may shrink after the reaction. Therefore, the content of the resinification catalyst is preferably 0.30 parts by mass or less. The content is more preferably 0.29 parts by mass or less, or 0.28 parts by mass or less.

[0067] [1.2.8. Content of foam stabilizer] The "content of foam stabilizer" refers to the mass of the foam stabilizer when the mass of the polyol component is 100. When two or more kinds of foam stabilizers are used, the "mass of foam stabilizer" refers to the total mass of two or more kinds of foam stabilizers.

[0068] If the content of the foam stabilizer is too small, it may be difficult to form the foam. Therefore, the content of the foam stabilizer is preferably 0.1 part by mass or more. The content is more preferably 0.2 part by mass or more, or 0.3 part by mass or more. On the one hand, when the content of the foam stabilizer becomes excessive, the foam may become closed cells and the air permeability may be impaired, or the foam may shrink after the reaction. Therefore, the content of the foam stabilizer is preferably 1.0 part by mass or less. The content is more preferably 0.8 part by mass or less, or 0.6 part by mass or less.

[0069] [1.3. Reaction] The polyisocyanate component (B liquid) is added to and mixed with the raw material mixture (A liquid) containing the polyol component and other additives, and the raw material mixture is maintained at a predetermined temperature. Thereby, a foaming reaction and a resinification reaction occur, and the polyurethane foam according to the present invention is obtained.

[0070] In addition, when manufacturing the polyurethane foam according to the present invention, either the slab foaming method or the mold foaming method may be used. "Slab foaming" refers to a method in which a raw material mixture for manufacturing a polyurethane foam is discharged onto a belt conveyor and foamed at normal temperature under atmospheric pressure. "Mold foaming" refers to a method of injecting a raw material mixture for producing polyurethane foam into the cavity of a mold and causing foaming within the cavity.

[0071] [1.4. Characteristics] [1.4.1. Volume resistivity] "Volume resistivity" refers to a value measured in accordance with JIS K6911:1995.

[0072] Since the polyurethane foam according to the present invention is produced from a raw material mixture containing an ionic compound, its volume resistivity is low. When the production conditions are optimized, the volume resistivity of the polyurethane foam becomes 1×10 10 Ω·cm or less. When the production conditions are further optimized, the volume resistivity becomes 5.0×10 9 Ω·cm or less, 1.0×10 9 Ω·cm or less, 9.0×10 8 Ω·cm or less, or 8.0×10 8 Ω·cm or less.

[0073] [1.4.2. 25% CLD hardness] "25% CLD hardness" refers to a value measured in accordance with ASTM D 3574-11.

[0074] When producing a polyurethane foam from a raw material mixture containing a quaternary ammonium salt, the hardness of the polyurethane foam may decrease. However, even when adding a quaternary ammonium salt to the raw material mixture, by optimizing the components contained in the raw material mixture and their contents, a decrease in hardness can be suppressed. When the production conditions are optimized, the 25% CLD hardness of the polyurethane foam becomes 2.0 kPa or more. When the production conditions are further optimized, the 25% CLD hardness becomes 2.5 kPa or more, 3.0 kPa or more, 4.0 kPa or more, or 5.0 kPa or more.

[0075] [1.5. Applications] The polyurethane foam according to the present invention can reduce the addition amount of an ionic compound (antistatic agent) containing PFAS while suppressing an increase in volume resistivity. Further, by using a polymer polyol and a crosslinking agent, it is possible to ensure hardness while maintaining a low volume resistivity. Therefore, the polyurethane foam according to the present invention can be used in various applications that require high conductivity and appropriate hardness.

[0076] Specifically, the polyurethane foam according to the present invention is (a) Packaging materials and cushioning materials for electronic components, electronic devices, etc., (b) Materials for rollers (printer rollers) inside image forming apparatuses, (c) Electromagnetic wave absorbing materials and the like.

[0077] [2. Printer Roller] The printer roller according to the present invention includes the polyurethane foam according to the present invention. In the present invention, the structure of the printer roller is not particularly limited, and an optimal structure can be selected according to the purpose. A printer roller generally includes a shaft and an elastic layer formed on the surface of the shaft. The polyurethane foam according to the present invention can be used for the elastic layer. Since the details of the polyurethane foam are as described above, the description is omitted.

[0078] [2. Action] When a quaternary ammonium salt having a specific molecular structure is added to a raw material mixture for producing a polyurethane foam, a polyurethane foam exhibiting high conductivity can be obtained even when the content of PFAS is small. This is considered to be because charges move through the cations and / or anions constituting the quaternary ammonium salt.

[0079] In addition, when a quaternary ammonium salt is added to the raw material mixture, the hardness of the polyurethane foam may decrease. On the other hand, when a polymeric polyol is used as the polyol component and / or a crosslinking agent is added to the raw material mixture, the decrease in hardness caused by the addition of the quaternary ammonium salt can be suppressed.

Examples

[0080] (Examples 1 to 48, Comparative Examples 1 to 15) [1. Preparation of Samples] [1.1. Raw Materials] The following polyols were used. (1) Polyether polyol 1: manufactured by Sanyo Chemical Industries, Ltd., "No. 38", OHV = 33.0, f = 3, molecular weight = 5000 (2) Polyether polyol 2: manufactured by Mitsui Chemicals, Inc., "Actocol (registered trademark) L-50", OHV = 56.0, f = 3, molecular weight = 3000 (3) Polymer polyol 1: manufactured by Wanhua Chemical Group, "WANOL F-3145P", OHV = 30.8, f = 3, molecular weight = 3000, polymer solid content ratio = 44.7% (4) Polymer polyol 2: manufactured by Sanyo Chemical Industries, Ltd., "Sunnex (registered trademark) FA-728R", OHV = 28.0, f = 3, molecular weight = 5000, polymer solid content ratio = 20.0% (5) Polymer polyol 3: manufactured by Covestro, "Hyperlite (registered trademark) E-850", OHV = 22, f = 3, molecular weight = 5000, polymer solid content ratio = 40.0%

[0081] The following catalysts and catalyst extenders were used. (1) Amine catalyst 1 (foaming catalyst): manufactured by Evonik Japan Co., Ltd., "Dabco (registered trademark) NE300", OHV = 276 (2) Amine catalyst 2 (resinification catalyst): manufactured by Kao Corporation, "Kao Resizer (registered trademark) No. 25", OHV = 387 (3) Metal catalyst (resinification catalyst: manufactured by Johoku Chemical Industry Co., Ltd., "MRH-110" (4) Metal catalyst defoamer: Sanyo Chemical Industries, Ltd., "GP-3050NS", OHV = 56.1, f = 3, molecular weight = 3000

[0082] The following were used as foam stabilizers. (1) Foam stabilizer 1: manufactured by Dow Corning Toray Co., Ltd., "SZ-1142" (2) Foam stabilizer 2: manufactured by Dow Corning Toray Co., Ltd., "SZ-1968", OHV = 140

[0083] The following were used as ionic compounds and crosslinking agents. (1) Ionic compound 1 (lithium bis(trifluoromethanesulfonyl)imide): manufactured by Sanko Chemical Industries Co., Ltd., "Sankonol (registered trademark) PEO-(B)-20R" (2) Ionic compound 2 (perchloric acid + quaternary ammonium salt): manufactured by NOF Corporation, "Cation IN" (3) Ionic compound 3 (1-butyl-3-methylpyridinium + hexafluorophosphate): manufactured by Nippon Carlit Co., Ltd., "CIL-625"

[0084] (4) Crosslinking agent 1: manufactured by ADEKA Corporation, "EDP-300", OHV = 760, f = 4, molecular weight = 300 (5) Crosslinking agent 2: manufactured by ADEKA Corporation, "GM-30", OHV = 550, f = 3, molecular weight = 300 (6) Ionic compound 4 (1-ethyl-3-methylimidazolium + p-toluenesulfonic acid): manufactured by Nippon Carlit Co., Ltd., "CIL-R50"

[0085] (7) Ionic compound 5 (amine salt): manufactured by Nippon Emulsion Co., Ltd., "Aminoion (registered trademark) AS300" (8) Ionic compound 6 (triethyl phosphate): manufactured by AVANZARE, "avanION5" (9) Ionic compound 7 (triethyl phosphate): manufactured by AVANZARE, "avanION13" (10) Ionic compound 8 (triethyl phosphate): manufactured by AVANZARE, "avanION510" (11) Ionic compound 9 (CAS No. 68348-88-9, C78H153O32B): manufactured by Boron Research Institute Co., Ltd., "Biomicelle (registered trademark) BN-1300"

[0086] The following polyisocyanates were used. (1) Polyisocyanate: manufactured by Mitsui Chemicals, Inc., "Cosmonate (registered trademark) T-65"

[0087] [1.2. Foam formation] The above raw materials were mixed at a predetermined ratio to obtain a raw material mixture. The raw material mixture was injected into an open-top non-sealed foam box, and the raw material mixture was freely foamed in the foam box. Further, the foam box containing the foam was placed in an oven set at 70°C to cure the foam. For Comparative Examples 3 and 5, a cardboard foam box with a size of 270 mm square was used. For the other examples and comparative examples, a cardboard foam box with a size of 170 mm square was used.

[0088] [2. Test method] The following physical property values of the obtained polyurethane foam were measured according to the following standards. (1) Density: JIS K 7222:2005 (2) 25% CLD hardness: ASTM D 3574-11 (3) 25% ILD hardness: JIS K 6400-2:2012 (4) Resilience: JIS K 6400-3:2011 (5) Cell count: Annex to JIS K 6400-1

[0089] (6) Tensile strength: JIS K 6400-5:2012 (7) Elongation: JIS K 6400-5:2012 (8) Tear strength: JIS K 6400-5:2012 (9) Dry heat distortion: JIS K 6400-4:2004 (10) ASTM ventilation: ASTM D 3574 (11)Volume resistivity JIS K 6911:1995

[0090] [3. Results] The results are shown in Tables 1 to 9. In Tables 1 to 9, the raw material formulations of each sample are also shown. Regarding the raw material formulations, the numerical values other than the index represent parts by mass each. From Tables 1 to 9, the following can be understood.

[0091] (1) Examples 1 to 6 are examples in which only the quaternary ammonium salt represented by the formula (1) is used as the ionic compound. In Examples 1 to 6, the volume resistivity was 8.07×10 9 ~8.29×10 8 Ω·cm. Also, the tendency was observed that the volume resistivity decreased as the addition amount of the quaternary ammonium salt increased. (2) Comparative Examples 1 to 2 are examples in which only the hexafluorophosphate represented by the formula (3) is used as the ionic compound. In Comparative Examples 1 to 2, the volume resistivity was 1.09×10 9 ~5.05×10 8 . Also, the tendency was observed that the volume resistivity decreased as the addition amount of the hexafluorophosphate increased. However, since the hexafluorophosphate used is a kind of PFAS, there are concerns about its impact on the environment.

[0092] (3) Examples 7 to 13 are examples in which the quaternary ammonium salt represented by the formula (1) and the hexafluorophosphate represented by the formula (3) are used in combination as the ionic compound. In Examples 7 to 13, the volume resistivity was 1.54×10 9 ~7.80×10 7 Ω·cm. Also, when the quaternary ammonium salt and the hexafluorophosphate were used in combination, the volume resistivity decreased compared to the case where only the hexafluorophosphate was added (Comparative Examples 1 and 2). (4) Examples 14 to 27 are examples in which the quaternary ammonium salt represented by the formula (1) and the bissulfonylimide salt represented by the formula (2) are used in combination as the ionic compound. In Examples 14 to 27, the volume resistivity was 3.69×10 8 ~3.34×10 9It became Ω·cm. Also, when a quaternary ammonium salt and a bis-sulfonylimide salt were used in combination, the volume resistivity tended to decrease compared to the case where only the bis-sulfonylimide salt was added (Comparative Examples 3 to 9).

[0093] (5) Examples 28 to 39 are examples in which a quaternary ammonium salt represented by formula (1) and a bis-sulfonylimide salt represented by formula (2) are used in combination as ionic compounds, and polymer polyol is used as the polyol component. As the addition amount of the polymer polyol increased, the 25% CLD hardness tended to increase. In particular, in Example 29, high hardness and low volume resistivity could be achieved at a high level. (6) Examples 40 to 48 are examples in which a quaternary ammonium salt represented by formula (1) and a bis-sulfonylimide salt represented by formula (2) are used in combination as ionic compounds, and a crosslinking agent is added to the raw material mixture. Also, Examples 43 to 45 are examples in which a polymer polyol is further added. As the addition amount of the crosslinking agent increased, the 25% CLD hardness tended to increase. Also, when the crosslinking agent and the polymer polyol were used in combination, the 25% CLD hardness tended to increase further. In particular, in Example 43, high hardness and low volume resistivity could be achieved at a high level.

[0094] (7) Comparative Example 3 is an example of a polyurethane foam that does not contain an ionic compound. In Comparative Example 3, the volume resistivity was 3.07×10 12 Ω·cm. (8) Comparative Examples 4 to 9 are examples in which only the bis-sulfonylimide salt represented by formula (2) is used as the ionic compound. In Comparative Examples 4 to 9, the volume resistivity was 1.99×10 9 ~7.24×10 8 Ω·cm. Also, as the addition amount of the bis-sulfonylimide salt increased, the volume resistivity tended to decrease. However, since the bis-sulfonylimide salt used is a type of PFAS, there are concerns about its impact on the environment.

[0095] (9) Comparative Example 4 and Comparative Example 5 are examples where only the foam size is different. It was found that when the formulation is the same, even if the foam size is different, substantially equivalent physical property values are exhibited. (10) Comparative Examples 10 to 17 are examples using ionic compounds other than the quaternary ammonium salt represented by formula (1), the bissulfonylimide salt represented by formula (2), and the hexafluorophosphate salt represented by formula (3). In Comparative Examples 10 to 11 and 13 to 17, the volume resistivity was all over 1×10 10 Ω·cm. Also, in Comparative Example 12, foam inhibition occurred, so the volume resistivity could not be measured.

[0096]

Table 1

[0097]

Table 2

[0098]

Table 3

[0099]

Table 4

[0100]

Table 5

[0101]

Table 6

[0102]

Table 7

[0103]

Table 8

[0104]

Table 9

[0105] As described above in detail regarding the embodiments of the present invention, the present invention is not limited to the above embodiments at all, and various modifications are possible without departing from the gist of the present invention.

Industrial Applicability

[0106] The polyurethane foam according to the present invention can be used as a cushioning material for packaging electronic components and electronic devices, a material for rollers (printer rollers) in an image forming apparatus, an electromagnetic wave absorbing material, and the like.

Claims

Claim 1 A polyurethane foam obtained by reacting and foaming a raw material mixture containing a polyol component, a polyisocyanate component, a blowing agent, and an ionic compound, wherein the ionic compound contains a quaternary ammonium salt represented by the following formula (1): provided that 【Chemical 1】 n is an integer of 1 or more. R 1 , R 2 , and R 3 is each an alkyl group having 1 to 18 carbon atoms, Claim 2 X - is a monovalent anion. Provided that the "volume resistivity" refers to a value measured in accordance with JIS K6911:1995. The polyurethane foam according to claim 1, having a volume resistivity of 1×10 10 Ω·cm or less. Claim 3 The polyol component contains polymer polyol, and / or the raw material mixture further contains a crosslinking agent, wherein the crosslinking agent is composed of an organic compound having 3 or more active hydrogen groups in one molecule and a molecular weight of 500 or less. The polyurethane foam according to claim 1. Claim 4 The polyurethane foam according to claim 1, wherein the 25% CLD hardness is 2.0 kPa or more. Provided that the "25% CLD hardness" refers to a value measured in accordance with ASTM D 3574-11. Claim 5 A printer roller provided with the polyurethane foam according to any one of claims 1 to 4. ​

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