JP2006348276A - Self-hinging molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-hinging molding having self-hinging quality and heat resistance (melting point) superior to those of nylon 6 and having rigidity (flexural modulus) at least equivalent to that of nylon 6. <P>SOLUTION: The self-hinging molding comprises a polyamide resin comprising adipic acid units and pentamethylenediamine units. It is desirable that the content of the adipic acid units is 90 wt.% or higher based on the dicarboxylic acid units and the content of the pentamethylenedaimine units is 90 wt.% or higher based on the diamine units, that the polyamide resin is obtained by polycondensing an aliphatic diamine containing pentamethylenediamine with a dicarboxylic acid containing adipic acid under heating, and that the pentamethylenediamine is produced from lysine by using lysine decarboxylase, cells that produce lysine decarboxylase or a treated product of the cells. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molded article with a hinge. More specifically, the present invention relates to a hinged molded article made of a polyamide resin having a hinge property and heat resistance (melting point) superior to those of 6 nylon and simultaneously having rigidity (flexural modulus) equal to or higher than that of 6 nylon.

  6 Nylon and 66 Nylon are resins with excellent moldability, heat resistance, chemical resistance, mechanical properties, etc., automobile / vehicle related parts, electrical / electronic related parts, home / office electrical product related parts, computer Used in a wide range of applications such as related parts, facsimile / copier-related parts, machine-related parts, packaging materials, and fishery-related materials. In particular, intake manifold, hinged clip (molded product with hinge), cable tie, resonator, air cleaner, engine cover, rocker cover, cylinder head cover, timing belt cover, gasoline tank, gasoline sub tank, radiator tank as automotive / vehicle related parts Application to automotive underhood parts such as intercooler tanks, oil reservoir tanks, oil pans, electric power steering gears, oil strainers, canisters, engine mounts, junction blocks, relay blocks, connectors, corrugated tubes, and protectors are being studied.

  Among these, many molded articles with hinges are used in underhood parts for automobiles. At present, 66 nylon is used when high heat resistance is required, and 6 nylon is used when high toughness is required. 66 nylon has a high melting point of 264 ° C., but its toughness is somewhat low due to its high crystallinity, and it is easily broken when the hinge part is bent. On the other hand, nylon 6 has better toughness due to lower crystallinity than 66 nylon, but its melting point is 224 ° C. and 40 ° C. lower than 66 nylon.

  In recent years, since the number of parts with hinges having a more complicated shape has increased, a polyamide resin having a hinge property superior to that of nylon 6 is desired. Moreover, since the engine room of a motor vehicle is made compact, a polyamide resin having higher heat resistance (melting point) is desired. Furthermore, it is desirable that these polyamide resins have a rigidity (flexural modulus) equal to or higher than that of 6 nylon.

  In order to satisfy the above requirements, a method of blending boron nitride powder and an aliphatic carboxylic acid derivative with a polyamide resin (for example, see Patent Document 1), a method of blending a polyamide resin with a polyolefin such as polypropylene or polyethylene (for example, a patent) Document 2) has been proposed. However, in the former polyamide resin composition, there is no knowledge about improvement in heat resistance (melting point), and it cannot be expected that improvement in heat resistance (melting point) can be expected based on common technical knowledge. In the latter polyamide resin composition, mechanical properties such as heat resistance (melting point) and flexural modulus are lower than those of the polyamide resin.

Moreover, as a polyamide resin composition that satisfies both hinge properties and heat resistance (thermal deformation temperature) at the same time, an aromatic polyamide resin, a modified polyolefin, an epoxy group-containing polymer or an epoxidized diene block copolymer, There is known a polyamide resin composition made of However, the bending elastic modulus of this type of polyamide resin composition is about 1500 to 1900 MPa, which is greatly inferior to the bending elastic modulus of ordinary 6 nylon (about 2550 MPa) and 66 nylon (about 2940 MPa), Rigidity important as mechanical properties is insufficient. Therefore, a hinged molded article made of a polyamide resin having a hinge property and heat resistance (melting point) superior to 6 nylon and simultaneously having a rigidity (bending elastic modulus) equal to or higher than 6 nylon has not been obtained. It is a fact.
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  In recent years, 56 nylon has been known as a polyamide resin produced by polymerization using biomass-derived raw materials. Substituting biomass-derived raw materials with polyamide-derived raw materials is highly anticipated for the prevention of global warming by controlling carbon dioxide emissions and the formation of a recycling-oriented society. It is desired to increase the ratio of biomass-derived raw materials in

  56 nylon has substantially the same heat resistance and mechanical properties as compared with 6 nylon and 66 nylon. 56 Nylon is produced by heating polycondensation of diaminopentane and adipic acid (for example, see Patent Document 5), or preparing a salt of diaminopentane and adipic acid and heating polycondensation (for example, Patent Document) 6) and the like are known. However, there is no knowledge about 56 nylon molded products with hinges.

JP 7-82474 A JP-A-9-249808 JP-A-9-124934 JP 2000-204243 A JP 2003-292612 A U.S. Pat. No. 2,130,948

  The present invention has been made in view of the above circumstances, and its purpose is to have hinge properties and heat resistance (melting point) superior to 6 nylon, and at the same time, rigidity (flexural modulus) is equal to or greater than 6 nylon. The present invention provides a hinged molded article made of a polyamide resin.

  In order to solve the above problems, the present inventors have intensively studied. As a result, the molded article with a hinge containing a polyamide resin composed of an adipic acid unit and a pentamethylenediamine unit has a hinge property, heat resistance (melting point) and rigidity ( It was found that the flexural modulus was satisfied at the same time, and the present invention was completed.

  The gist of the present invention resides in a hinged molded article containing a polyamide resin composed of adipic acid units and pentamethylenediamine units.

  The hinged molded article of the present invention exhibits extremely high hinge characteristics, and has higher heat resistance (melting point) than a hinged molded article made of 6 nylon, and mechanical properties almost equal to or higher than that of a hinged molded article made of 6 nylon. Therefore, it is particularly suitable for a hinged part in an automobile engine room and useful as various hinged parts. Furthermore, for hinged molded products made of polyamide resin using biomass-derived raw materials, the effect on reducing environmental impact can be expected.

  Hereinafter, the present invention will be described in detail. However, the description of the constituent elements described below is a representative example of embodiments of the present invention, and the present invention is not limited to these contents. The hinged molded article of the present invention contains a polyamide resin composed of an adipic acid unit and a pentamethylenediamine unit, and may be composed only of the polyamide resin.

  The content of adipic acid units in the dicarboxylic acid units constituting the polyamide resin is usually 90% by weight or more, preferably 95% by weight or more, and may be composed of only adipic acid units. The content of pentamethylenediamine units in the diamine units constituting the polyamide resin is usually 90% by weight or more, preferably 95% by weight or more, and may be composed only of pentamethylenediamine units. In addition, the structural unit of a polyamide resin can be calculated | required with the following methods, for example. That is, after the polyamide resin is hydrolyzed with an acid or alkali, measurement is performed by a liquid chromatography method or the like. And the content of each structural unit is calculated | required using the analytical curve created beforehand.

  The polyamide resin in the present invention is a component other than pentamethylenediamine and adipic acid, which are essential structural units, as long as it is generally less than 10% by weight, preferably less than 5% by weight, and does not impair the effects of the present invention. Units may be included. Examples of other structural units include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and paraaminomethylbenzoic acid.

  In addition, as other structural units, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassic acid, tetradecanedioic acid, Examples thereof include aliphatic dicarboxylic acids such as pentadecanedioic acid and octadecanedioic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid.

  Further, as other structural units, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13-diaminotridecane, 1,14-diaminotetradecane, 1,15-diaminopentadecane, 1,16-diaminohexadecane 1,17-diaminoheptadecane, 1,18-diaminooctadecane, 1,19-diaminononadecane, 1,20-diaminoeicosane, aliphatic diamine such as 2-methyl-1,5-diaminopentane, cyclohexanediamine Alicyclic diamine such as bis- (4-aminohexyl) methane , Aromatic diamines such as xylylenediamine.

  The degree of polymerization of the polyamide resin in the present invention is not particularly limited, and the relative viscosity of the polyamide resin 98 wt% sulfuric acid solution (polyamide resin concentration: 0.01 g / ml) at 25 ° C. is usually 1.5 to 8.0. , Preferably 1.8 to 5.0. When the relative viscosity is less than 1.5, the practical strength may be insufficient, and when it exceeds 8.0, the fluidity may be lowered and the moldability may be impaired.

  The melting point (Tm) of the polyamide resin in the present invention is usually two, about 255 ° C. and about 232 ° C. The melting point is measured using, for example, “Robot DSC” manufactured by Seiko Denshi Kogyo. As a specific operation method, about 5 mg of the obtained polyamide resin was put in a sample pan, heated to 290 ° C. in a nitrogen atmosphere, and held for 3 minutes. Thereafter, the temperature is decreased to 30 ° C. at a temperature decreasing rate of 20 ° C./min. Subsequently, after holding at 30 ° C. for 3 minutes, an endothermic peak observed when the temperature is increased from 30 ° C. to 290 ° C. at a temperature increase rate of 20 ° C./min is measured and set as the melting point.

  As the method for producing the polyamide resin in the present invention, known methods can be used, and specifically disclosed in “Polyamide Resin Handbook” (published by Nikkan Kogyo Co., Ltd .: Osamu Fukumoto). The polyamide resin in the present invention is preferably obtained by polycondensation of an aliphatic diamine containing pentamethylenediamine and a dicarboxylic acid containing adipic acid. More specifically, a method (heat polycondensation) in which a salt of pentamethylenediamine and adipic acid is prepared, these are mixed in the presence of water, and heated to advance the dehydration reaction is preferable. The molar ratio of aliphatic diamine to dicarboxylic acid is preferably in the range of 1.00 to 1.05: 1. If it is out of the above range, the polymerization rate may decrease.

  In the present invention, the above-mentioned heat polycondensation is a method in which the maximum reached temperature of the polymerization reaction mixture during the production of the polyamide resin is increased to 200 ° C. or higher. The upper limit of the maximum temperature reached is usually 300 ° C. or lower in consideration of the thermal stability of the polyamide resin during the polymerization reaction. The polymerization method may be a batch method or a continuous method.

  The polyamide resin produced by the above method can be further subjected to solid phase polymerization after heat polycondensation. Thereby, the molecular weight of the polyamide resin can be increased. The solid phase polymerization can be performed by heating in a vacuum or an inert gas at a temperature of 100 ° C. or higher and a melting point or lower, for example.

  In the polyamide resin of the present invention produced by the above method, pentamethylenediamine as a raw material component is produced from lysine using cells that produce lysine decarboxylase, lysine decarboxylase, or processed products of the cells. It is preferable. Thereby, the biomass ratio (the ratio of the biomass-derived raw material in the used raw material of the polyamide resin) can be increased. The polyamide resin in the present invention preferably has a biomass ratio (ratio of the biomass-derived raw material in the raw material used for the polyamide resin) of 25% or more. If it is less than 25%, the effect of suppressing the generation of carbon dioxide causing global warming cannot be obtained.

  Specifically, the above pentamethylenediamine can be produced, for example, by the following method. That is, lysine is subjected to enzymatic decarboxylation while adding an acid to the lysine solution so that the pH of the solution is maintained at a pH suitable for enzymatic decarboxylation. Examples of the acid used here include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, and organic acids such as acetic acid. Free pentamethylene diamine can be collected from the obtained reaction product solution by an ordinary separation and purification method. In addition, when a dicarboxylic acid such as adipic acid is used as the acid, pentamethylenediamine dicarboxylic acid salt as a raw material for producing polyamide can be directly collected. A method for producing pentamethylenediamine / adipate by enzymatic decarboxylation of lysine using adipic acid as an acid is described in JP-A-2005-6650.

  In the polyamide resin of the present invention, other components can be blended at any stage from the production (polycondensation) of the polyamide resin to the molding as long as the effects of the present invention are not impaired. Other components include crystal nucleating agents, antioxidants and / or heat stabilizers, weathering agents, release agents and / or lubricants, pigments, dyes, plasticizers, antistatic agents, flame retardants, and other polymers. Can be mentioned.

  Examples of the crystal nucleating agent include inorganic fine particles such as talc, kaolin, silica, and boron nitride, metal oxides, high melting point nylon, and the like. Examples of the antioxidant and / or heat stabilizer include hindered phenols, hydroquinones, phosphites, and substituted products thereof, copper halides, iodine compounds, and the like. Examples of the weathering agent include resorcinol, salicylate, benzotriazole, benzophenone, hindered amine and the like. Examples of release agents and / or lubricants include aliphatic alcohols, aliphatic amides, aliphatic bisamides, bisureas, and polyethylene waxes. Examples of the pigment include cadmium sulfide, phthalocyanine, carbon black and the like. Examples of the dye include nigrosine and aniline black. Examples of the plasticizer include octyl p-oxybenzoate and N-butylbenzenesulfonamide.

  Examples of the antistatic agent include an alkyl sulfate type anionic antistatic agent, a quaternary ammonium salt type cationic antistatic agent, a nonionic antistatic agent such as polyoxyethylene sorbitan monostearate, and a betaine amphoteric antistatic agent. It is done. Flame retardants include hydroxides such as melamine cyanurate, magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate, brominated polystyrene, brominated polyphenylene oxide, brominated polycarbonate, brominated epoxy resins or brominated flame retardants thereof. And a combination of antimony trioxide and the like. Other polymers include other polyamides, polyethylene, polypropylene, polyester, polycarbonate, polyphenylene ether, polyphenylene sulfide, liquid crystal polymer, polysulfone, polyethersulfone, ABS resin, SAN resin, polystyrene, and the like.

  Above all, when using a polyamide resin for non-strengthening for injection molding such as hinged molded articles and binding bands, crystal nucleating agents and mold release agents are dry blended within the range that does not impair the present invention in order to improve moldability. It is preferable to mix.

  The hinged molded article of the present invention is obtained by molding into a desired shape by an arbitrary molding method using the polyamide resin of the present invention. Examples of the molding method include injection molding, film molding, melt spinning, blow molding, vacuum molding and the like, and injection molding is particularly preferable.

  Specific examples of the molded article with a hinge include a clip with a hinge, a connector with a hinge, a binding band with a hinge, and the thickness of the hinge part is usually 0.2 to 0.8 mm, preferably 0.3 to 0. .6 mm. When the thickness of the hinge part is less than 0.2 mm, the fluidity of the polyamide resin in the hinge part may deteriorate. If the thickness of the hinge part exceeds 0.8 mm, the crystallinity in the hinge part increases, and the hinge part may be easily broken when bent.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded. Below, the evaluation method of the various characteristics of a polyamide resin and a molded article with a hinge is demonstrated.

(1) Relative viscosity (ηr):
A 98% sulfuric acid solution of polyamide resin (concentration: 0.01 g / ml) was prepared and measured at 25 ° C. using an Ostwald viscometer.

(2) Analysis of adipic acid unit and 6-aminocaproic acid unit in polyamide resin:
After the sample was hydrolyzed with 6N hydrochloric acid, the obtained hydrolyzate was neutralized by adding a 1N sodium hydroxide aqueous solution dropwise to obtain a hydrolyzed stock solution. An HPLC mobile phase (0.01 M-octanesulfonic acid / acetonitrile = 85/15 (volume)) was added to this hydrolysis stock solution to obtain an analytical sample solution. This analytical sample solution was analyzed by liquid chromatography (Agilent HP-1100). The analysis conditions were as follows: column: “CAPCELL PAK C18 MG S-3” 4.6 ml. D. × 75 mm, column temperature: 40 ° C., mobile phase: 0.01 M-octanesulfonic acid / acetonitrile = 85/15 (volume), flow rate: 1 ml / min, detector: PDA (UV205 nm), injection amount: 5 μl . After the analysis, the content of the structural unit was determined using a calibration curve prepared in advance.

(3) Analysis of pentamethylenediamine units in polyamide resin:
After hydrolyzing the sample with 6N hydrochloric acid, the resulting hydrolyzate was evaporated to dryness on a rotary evaporator, dried at 40 ° C under reduced pressure for 1 hour, and then acylated with trifluoroacetic anhydride. It was. Excess trifluoroacetic anhydride was distilled off with a rotary evaporator and then dissolved in acetonitrile to obtain an analytical sample solution. This analytical sample solution was analyzed by gas chromatography. The analysis conditions were as follows: Column: “SPB-1 SULFUR” 30 m × 0.32 ml. D. , 4.00 μm film thickness, carrier: He 2.0 ml / min (Constant Flow Mode), column temperature: 80 ° C. (0 min) to 10 ° C./min to 280 ° C. (30 min), inlet temperature: 230 ° C., Split Ratio = 20: 1, injection volume: 1 μl. After the analysis, the content of the structural unit was determined using a calibration curve prepared in advance.

(4) DSC (differential scanning calorimetry):
This was performed using a “Robot DSC” manufactured by Seiko Denshi Kogyo. First, about 5 mg of polyamide resin was placed in a sample pan, heated to 290 ° C. in a nitrogen atmosphere, and held for 3 minutes. Thereafter, the temperature is decreased to 30 ° C. at a temperature decreasing rate of 20 ° C./min. Subsequently, after being held at 30 ° C. for 3 minutes, an endothermic peak observed when the temperature was increased from 30 ° C. to 290 ° C. at a temperature increase rate of 20 ° C./min was measured. The temperature of the observed endothermic peak was defined as the melting point (Tm), and when a plurality of endothermic peaks were detected, the melting point was defined as a plurality of melting points.

(5) Mechanical property evaluation (tensile test, bending test, notched Charpy test):
Glass fiber reinforced polyamide resin compositions and non-reinforced polyamide resin compositions were used, and ISO test pieces were molded in accordance with ISO standards. For the molding, a J75EII type injection molding machine manufactured by Nippon Steel Co., Ltd. is used. In the case of a glass fiber reinforced polyamide resin composition, the resin temperature is 270 ° C., the mold temperature is 80 ° C., and in the case of an unreinforced polyamide resin composition, the resin temperature. Each was performed at 265 ° C. and a mold temperature of 80 ° C. Using the obtained ISO test pieces, a tensile test, a bending test, and a notched Charpy test were performed in accordance with ISO standards.

(6) Low temperature hinge property:
Using a non-reinforced polyamide resin composition, a hinged molded article shown in FIG. 1 was molded. The molded article with the hinge was molded using a PS40 type injection molding machine manufactured by Nissei Plastic Industry Co., Ltd. at a resin temperature of 265 ° C. and a mold temperature of 80 ° C. The binding band was molded using a SE50D injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. at a resin temperature of 265 ° C. and a mold temperature of 80 ° C. The hinge part had a length of 2 mm, a width of 40 mm, and a wall thickness of 0.4 mm.

  The hinged molded article was cooled for 2 hours at the temperature shown in Table 1 in a thermostatic bath. In addition, the thermostat used the big thing which a tester entered and can test in. After cooling for 2 hours, the measurer enters the room, waits for 10 minutes in the thermostatic bath to completely eliminate the influence of the temperature change at the time of entry, and then, as shown in FIG. The test was performed from a bent state) to 180 degrees (a flat state with respect to the floor surface). Specifically, a test was performed in which the horizontal surface of the molded product was held with one hand and the vertical surface of the molded product was quickly bent with the other hand. The test was performed on 20 hinged molded articles at each temperature, and the number of hinge parts that did not break was used as a measured value.

  In the following examples and comparative examples, Rhodia “AH salt” was used as an equimolar salt of hexamethylenediamine and adipic acid. Further, an equimolar salt of pentamethylenediamine and adipic acid was prepared according to the method described in Examples 1 to 3 of JP-A-2005-6650.

Example 1:
After adding 25 kg of water to 25 kg of equimolar salt of pentamethylenediamine and adipic acid, 1.25 g of phosphorous acid was added, and the mixture was completely dissolved under a nitrogen atmosphere to obtain a raw material aqueous solution. The raw material aqueous solution was transferred to an autoclave which had been previously purged with nitrogen by a plunger pump. The jacket temperature was adjusted to 280 ° C., the autoclave pressure was adjusted to 1.47 MPa, and the contents were heated to 270 ° C. Next, after gradually releasing the pressure in the autoclave, the pressure was further reduced and the reaction was terminated when a predetermined stirring power was reached. After completion of the reaction, the pressure was restored with nitrogen, and the contents were introduced into a cooling water tank in the form of a strand and then pelletized with a rotary cutter. The obtained pellets were dried under the conditions of 120 ° C. and 1 torr (0.13 kPa) until the water content became 0.1% or less to obtain a polyamide resin. Various analytical characteristics of the obtained polyamide resin were evaluated. The results are shown in Table 1.

  0.02 part by weight of talc having an average particle size of 3.0 μm as a crystal nucleating agent was blended with 100 parts by weight of the obtained polyamide resin and then dry blended to obtain an unreinforced polyamide resin composition. Each evaluation of low temperature hinge property and mechanical property was performed with respect to the obtained polyamide resin composition. The results are shown in Table 1.

Comparative Example 1:
25 kg of caprolactam manufactured by Mitsubishi Chemical Co., Ltd., 0.75 kg of water, and 1.74 g of disodium hydrogen phosphite pentahydrate were put in a container, purged with nitrogen, and dissolved at 100 ° C. This raw material aqueous solution was transferred to an autoclave, the jacket temperature was set to 280 ° C., and heating was started. After the temperature of the contents was raised to 270 ° C., the pressure in the autoclave was gradually released, and then the pressure was further reduced and the polycondensation reaction was completed when the predetermined stirring power was reached. After completion of the reaction, the pressure was restored with nitrogen, and the contents were introduced into a cooling water tank in the form of a strand and then pelletized with a rotary cutter. Unreacted monomers and oligomers were extracted and removed from the obtained pellets using boiling water 1.5 times the amount of the obtained pellets. The pellets from which the unreacted substances had been removed were dried at 120 ° C. and 1 torr (0.13 kPa) until the water content became 0.1% or less to obtain a polyamide resin. Various analytical characteristics of the obtained polyamide resin were evaluated.

  In the same manner as in Example 1, talc was blended and then dry blended to obtain a non-reinforced polyamide resin composition. Each evaluation of low temperature hinge property and mechanical property was performed with respect to the obtained polyamide resin composition. The results are shown in Table 1.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the invention is not limited to the embodiments disclosed herein. It should be understood that the present invention can be modified as appropriate without departing from the spirit or concept of the invention as read from the claims and the entire specification, and that such changes are also within the technical scope of the present invention. .

It is the side view (a) and top view (b) of the molded article with a hinge used for the low temperature hinge property test in the Example of this invention. It is explanatory drawing of the low temperature hinge property test in the Example of this invention.

Claims (5)

  A hinged molded article containing a polyamide resin composed of adipic acid units and pentamethylenediamine units.   The hinged unit according to claim 1, wherein the content of the adipic acid unit in the dicarboxylic acid unit constituting the polyamide resin is 90% by weight or more, and the content of the pentamethylenediamine unit in the diamine unit is 90% by weight or more. Molding.   The molded article with hinge according to claim 1 or 2, wherein the polyamide resin is obtained by heat polycondensation of an aliphatic diamine containing pentamethylenediamine and a dicarboxylic acid containing adipic acid.   The molded article with hinge according to claim 1 or 2, wherein the polyamide resin is obtained by heating polycondensation of a salt of pentamethylenediamine and adipic acid.   The hinged molded article according to claim 3 or 4, wherein pentamethylenediamine is produced from lysine using lysine decarboxylase, a cell producing lysine decarboxylase, or a treated product of the cell.