JP2001104729A - Decomposable filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter solving a refuse treatment problem of a dust collection filter made of polyethylene or polyurethane and not consuming precious forest resources like a paper filter. SOLUTION: A decomposable filter comprises foam based on poly (lactic acid).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention has a biodegradable function,
The present invention relates to a decomposable filter having practical utility as a dust filter for an air conditioner, a dust collector, a suction device, and the like.

[0002]

2. Description of the Related Art In recent years, there has been a shortage of landfill sites, which are final disposal sites, and the disposal of plastic products has become a serious problem. Plastic products are used in a very large number of products because of their low cost and excellent functions, and most of them are disposable because of their low cost. In air conditioners such as air purifiers, air conditioners, ventilation fans, and fan heaters, a porous body made of polyethylene, polyurethane, or the like is used as a filter to remove dust. Although these materials are regularly cleaned and used, since it is difficult to completely remove dust, they are replaced as consumables in a short period of time. Filters after replacement contain a lot of oil and dust inside and cannot be recycled, so they are currently buried or incinerated.

[0003] Paper filters are used in order to cope with the disposal problem, but the paper filters are disposable because they are weak to water and cannot be washed. To ensure dust removal performance,
High quality virgin pulp was used, which helped deplete valuable forest resources.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problem of refuse disposal of dust filters made of polyethylene, polyurethane, etc., as described above, and provides valuable forest resources such as paper filters. It is intended to provide a filter having a dust removal performance as a filter without consuming the same.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that polylactic acid, which is a biodegradable resin, is molded into a foam having open cells to form a degradable filter. The inventors have found that the problem can be solved, and have reached the present invention. That is, the gist of the present invention is as follows. A degradable filter comprising a foam containing polylactic acid as a main component.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The degradable filter of the present invention needs to use polylactic acid as a main component. The polylactic acid resin has properties equivalent to that of a synthetic resin under a normal use environment and does not change the use state, but shows degradability in a waste environment. For example, it is first degraded in the presence of soil microorganisms in an environment such as landfill or in compost. Also, polylactic acid resin, unlike other biodegradable resins such as polycaprolactone and polybutylene succinate, has excellent mold resistance, can prevent the occurrence of mold and the like, and has an unpleasant odor There is no occurrence and clean state can always be maintained. Furthermore, polylactic acid resin has very high chargeability,
Suspended particles can be efficiently captured by the electrostatic mechanism. In addition, since air conditioning equipment such as air purifiers, air conditioners, ventilation fans, and fan heaters are installed mainly in living spaces, dust that is removed from the filter contains a large amount of oil and protein components. Sex filters can degrade at a very fast rate in compost.

The polylactic acid used in the present invention includes polylactic acid, a copolymer of lactic acid and another hydroxycarboxylic acid, or a mixture thereof. As other hydroxycarboxylic acids, glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid and the like are used. The number average molecular weight of the polylactic acid resin used in the present invention is from 50,000 to 300,000, preferably from 80,000 to 200,000. If the number average molecular weight is less than 50,000, mechanical strength that can withstand practical use cannot be obtained, and if the number average molecular weight exceeds 300,000, molding processing becomes difficult and it becomes difficult to obtain a foam having a high foaming ratio. Further, D-lactic acid may be copolymerized or mixed.

The temperature 2 of the polylactic acid resin used in the present invention
The melt viscosity at 00 ° C. and a shear rate of 100 sec ⁻¹
1.0 × 10 ^{3 to} 1.0 × 10 ⁶ poise, preferably 3.
0 × 10 ^{3 to} 7.0 × 10 ⁵ poise, and 5.0 × 10 5
^{3 to} 5.0 × 10 ⁵ poise is particularly preferred. 1.0 × 10
^{If the} viscosity is less than ³ poise, bubbles cannot be formed because the viscosity is too low. On the other hand, if it exceeds 1.0 × 10 ⁶ poise, bubbles cannot be formed because the viscosity is too high. A nozzle having a diameter of 1.0 mm and an L / D of 10 was used for measuring the melt viscosity.

Further, a crosslinking agent and a curing accelerator can be added as needed to adjust the melt viscosity of the polylactic acid resin. Examples of the crosslinking agent include an epoxy compound, an isocyanate, an organic peroxide having a decomposition temperature equal to or higher than the melting point of the resin, or a mixture thereof.

Examples of epoxy compounds include bisphenol A type diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, terephthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, and phthalic acid diglycidyl ester. , 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis (3,4-epoxycyclohexyl)
Adipate, glycidyl 1,14-tetradecanedicarboxylate, and the like can be used.

Examples of the isocyanate include hexamethylene diisocyanate, 2,4-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, diisocyanate-modified polyether, and diisocyanate-modified isocyanate. Polyester, a compound obtained by modifying a polyhydric alcohol with a bifunctional isocyanate, a polyether modified with a polyvalent isocyanate, a polyester modified with a polyvalent isocyanate, and a mixture thereof.

As the organic peroxide, dicumyl peroxide, cumene hydroperoxide, methyl ethyl ketone peroxide, t-butylperoxyisopropyl carbonate, 1,1-bis (t-butylperoxy) cyclododecane, n-butyl -4,4-bis-t-
Butylperoxyvalerate, t-butylperoxybenzoate, t-butylperoxy-2-ethylhexanoate, di-t-butyl peroxide, di (t-butylperoxy) -m-diisopropylbenzene, 2,
5-dimethyl-2,5-di-t-butylperoxyhexane, 2,5-dimethyl-2,5-t-butylperoxylhexane-3, t-butylperoxycumene, benzoyl peroxide and the like are used. .

As the curing accelerator, cobalt naphthenate, cobalt octoate, manganese naphthenate, copper naphthenate, zinc naphthenate, laurylmercaptan, dimethylaniline, triethanolamine, diethylenetriamine, pyridine, piperidine and the like are used.

Further, the melting point of the polylactic acid resin used in the present invention is preferably from 100 to 175 ° C., more preferably from 120 to 170 ° C. 10
If it is lower than 0 ° C., the heat resistance is insufficient, and if it exceeds 175 ° C., it is difficult to manufacture.

When a polylactic acid resin is used for the decomposable filter of the present invention, in addition to a plasticizer, an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, a flame retardant, a light stabilizer, a filler, a pigment, etc. Can also be used together. As the plasticizer, diisodecyl phthalate, di-2-ethylhexyl phthalate, dibutyl phthalate, diisodecyl adipate, diisononyl adipate, di-n-alkyl adipate,
Di-2-ethylhexyl adipate, diisobutyl adipate, di-2-ethylhexyl sebacate, di-2-
Ethylhexyl sebacate, dibutyl sebacate, di-
2-ethylhaysyl azelate, di-2-hexyl azelate, acetyl tributyl citrate, diethyl succinate, dibutyl succinate, dioctyl adipate, diethyl sebacate, dibutyl sebacate, dibutyl sebacate, dibutyl azelate, tributyl Octyl trimellitate, diethyl phthalate, polypropylene glycol adipic acid, polyethylene glycol adipic acid, butanediol adipate and the like can be mentioned.

Examples of the antioxidant include hindered phenolic antioxidants such as pt-butylhydroxytoluene and pt-butylhydroxyanisole, and sulfur such as distearylthiodipropionate and dilaurylthiodipropionate. Antioxidants and the like.

Examples of the heat stabilizer include triphenyl phosphite, trilauryl phosphite, and trisnonylphenyl phosphite. Examples of the ultraviolet absorber include pt-butylphenyl salicylate and 2-hydroxy-4-methoxybenzophenone. -Hydroxy-4-methoxy-
2'-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone and the like, lubricants such as calcium stearate, zinc stearate, barium stearate and sodium palmitate, and hexabromocyclododecane, tris- (2, 3-dichloropropyl) phosphate, pentabromophenyl allyl ether and the like.

The filler includes an inorganic filler and an organic filler, and the inorganic filler includes diatomaceous earth, calcined barite, zeolite, kaolin, bentonite, silica, clay, glass, limestone, calcium silicate, calcium sulfate, aluminum oxide , Magnesium carbonate, ferric carbonate, and the like. Examples of the organic filler include wood powder, starch, cellulose, and cellulose derivatives, and examples of the pigment include titanium oxide and carbon black.

The foaming agent for forming the decomposable filter of the present invention is not particularly limited, but may be appropriately selected depending on the melting point of the resin used and the processing temperature. Chemical foaming agents such as volatile foaming agents, and physical foaming agents such as volatile liquids, inert gases, hydrocarbons, and halogenated hydrocarbons can be used.

For example, chemical blowing agents such as p-toluenesulfonylhydrazide, 4,4'-oxybis (benzenesulfonylhydrazide), dinitrosopentamethylenetetramine, azodicarbonamide, hydrazodicarbonamide, 5-phenyltetrazole, 4-phenyltetrazole, Aminourazole, lithium acetate, sodium acetate, potassium acetate, magnesium acetate, calcium acetate, calcium propionate, magnesium butyrate, sodium caprylate, sodium caprate, magnesium laurate,
Examples include calcium stearate, potassium stearate, calcium myristate, calcium benzoate, potassium terephthalate, calcium carbonate, sodium bicarbonate, sodium carbonate, sodium ethoxide, potassium phenoxide, calcium oxide, sodium oxide, magnesium oxide, and the like.

The physical foaming agents include methane, ethane, butane, hexane, cyclohexane, ethylcyclopentane, benzene, xylene, methyl chloride, methylene chloride,
Chloroform, carbon tetrachloride, ethyl chloride, dichloroethane, dichloroethylene, carbon tetrafluoride, ethyl fluoride, ethane tetrafluoride, chlorodifluoroethane, dichlorofluoromethane, chlorotrifluoromethane, dichlorodifluoromethane, trichlorofluoromethane, dichlorotetra Fluoroethane, trichlorotrifluoroethane, tetrachlorodifluoroethane, fluorobenzene, chlorobenzene, methylal, acetal, 1,4-dioxane, acetone, ethyl methyl ketone, acetylacetone, carbon dioxide gas, nitrogen gas, neon, helium, xenon, etc. .

The blowing agent may be used alone or in combination of two or more. The addition ratio of the foaming agent is 0.05 to
A range of 50% by weight is preferred. The addition ratio of the foaming agent is 0.
If it is less than 05%, practically no foaming is produced, so that a practical filter cannot be obtained. On the other hand, if the proportion of the foaming agent is more than 50% by weight, the foaming agent cannot enter the molten resin, and the gas blows out, making it difficult to obtain a filter having a predetermined shape.

In addition, nucleating agents such as talc, silica fine powder, sodium citrate, calcium carbonate, sodium carbonate and the like, and urea-based, organic acid-based, metal salt-based and the like, which are usually used to facilitate foam molding. A foaming aid can be used.

The decomposable filter of the present invention comprises a low-cost foam obtained by foam molding. In general, the cells in the foam are a mixture of open cells in which the cells are continuous and closed cells in which the cells are independent. However, the foam used for the decomposable filter of the present invention has the open cells having a volume fraction of 10% or more. It is necessary to contain. 1 open cell in the foam
If it is less than 0%, when it is used as a filter, the airflow resistance increases, the amount of retained dust decreases, and clogging occurs in a short period of time.

The decomposable filter of the present invention may be processed into any shape as long as it can efficiently remove dust in the air, but is usually a plate, tube, or cone. Often used. The thickness of the decomposable filter is preferably from 1 to 3000 mm. When the thickness is 1 mm or less, the amount of dust held is small, and the thickness is 3 mm.
If it is 000 mm or more, the ventilation resistance increases and the load on the air conditioner and the like increases.

The decomposable filter of the present invention preferably has a dust particle collection rate of 20% or more, particularly preferably 40% or more. If the dust particle collection rate is less than 20%, it is difficult to say that the filter functions as a filter. The decomposable filter of the present invention has a pressure loss of 0.5MP.
a, and preferably 0.3 MPa or less. When the pressure loss exceeds 0.5 MPa,
The load on the air conditioning equipment and the like increases, and the energy loss increases. The dust particle collection rate and pressure loss were measured according to JIS.
B9908 This is a value obtained by measurement according to format 3.

The method for producing the decomposable filter of the present invention includes an extrusion foaming method in which foaming is performed simultaneously with extrusion molding, a foaming molding method by injection molding, and after extrusion, heating under pressure and normal pressure. Any method such as a method of foaming can be used. For example, a resin is extruded into a plate-shaped mold attached to the tip of an extruder by the above-mentioned extrusion foaming method, and is subjected to foam molding at the same time as extrusion to obtain a plate-shaped degradable filter. Also, by changing the shape of the mold attached to the tip of the extruder arbitrarily, a three-dimensional decomposable filter such as a cylindrical shape or a conical shape can be molded. Also, a decomposable filter having a desired shape can be obtained by extruding from a T-die by the foam molding method, forming a sheet-like foam, and performing secondary processing such as a vacuum molding method, a pressure molding method, and a hot press. Can be. In order to increase the number of open cells in the filter, the foam may be mechanically squeezed to break the resin film between the closed cells to form open cells.

[0028]

The decomposable filter of the present invention can efficiently remove dust by using a foam having open cells made of a biodegradable resin containing polylactic acid as a main component.
An environment-friendly degradable filter that has excellent mold resistance and can be biodegraded in compost can be realized.

[0029]

Next, the present invention will be described specifically with reference to examples. The test methods used in the examples and comparative examples are as follows. (1) Dust particle collection rate and pressure loss Measurement was performed by a method according to JIS B9908 type 3. (2) Decomposability in compost The decomposable filter was left in a compost compost at a temperature of 60 ° C. and a humidity of 70%. After 10 days, the filter was taken out. (3) Mold resistance Measurement was carried out by a method according to JIS Z2911. The judgment is: 2/3 or more,: 1/3 to 2/3,
: 1/3 or less,: Not recognized.

Example 1 0.5% by weight of talc as a foaming nucleating agent, 2% by weight of benzoyl peroxide as a crosslinking agent, and a crosslinking accelerator in polylactic acid having a number average molecular weight of 100,000 (ECOPLA, manufactured by Cargill Dow Polymers) A mixture containing 5% by weight of dimethylaniline as a cylinder having a cylinder diameter of 40 mm and L /
The mixture was melt-mixed with a single screw extruder of D = 36, butane was blown in at 10% by weight as a foaming agent in the middle of the barrel, and then extruded from a T-die to obtain a continuous foam sheet having a thickness of 20 mm and a width of 380 mm. The temperature conditions are as follows: supply zone 170 ° C, plasticizing zone 180 ° C, melting zone 170 ° C, die part 145-1.
55 ° C. After cooling, the obtained foamed sheet is
A 300 mm-sided square was cut out to obtain a degradable filter having a good appearance. Table 1 shows the test results of the obtained degradable filters.

Example 2 A good appearance was obtained in the same manner as in Example 1 except that 20% by weight of cyclohexane was used as a foaming agent and 3% by weight of dicumyl peroxide was used as a cross-linking agent, and the mixture was extruded into a circular mold. A conical degradable filter having a height of 300 mm and a bottom diameter of 300 mm was obtained. Table 1 shows the test results of the obtained degradable filters.

Example 3 The same method as in Example 1 except that 2.3% by weight of isopentane was used as a foaming agent and 3% by weight of t-butyl perbenzoate as a cross-linking agent was used. A degradable filter having a good appearance and a thickness of 100 mm was obtained. Table 1 shows the test results of the obtained degradable filters.

Example 4 A mixture containing 0.5% by weight of calcium carbonate as a foam nucleating agent in polylactic acid having a number average molecular weight of 120,000 (ECOPLA, manufactured by Cargill Dow Polymers) having a cylinder diameter of 40 mm and an L / D = 36 was used. Melt and mixed in a single screw extruder, 10% by weight of azodicarbonamide as a foaming agent,
After press-fitting 1% by weight of zinc oxide as a foaming aid and 2.3% by weight of dicumyl peroxide as a cross-linking agent, it was extruded from a T-die to obtain an unfoamed sheet having a thickness of 1 mm and a width of 380 mm. The temperature conditions were as follows: supply zone 170 ° C, plasticizing zone 1
80 ° C, melting zone 170 ° C, die part 145-165 ° C
Met. After cooling, the obtained foamed sheet was sized to 30 mm in diameter.
A 0 mm disk was cut out and subjected to hot foam molding at 200 ° C. using a hot press molding machine having a disk-shaped mold to obtain a decomposable filter having a thickness of 20 mm and a diameter of 300 mm with a good appearance. Table 1 shows the test results of the obtained degradable filters.

Example 5 A 10 mm-thick foamed sheet obtained by the same method as in Example 1 except that 7% by weight of cyclohexane and 5% by weight of azodicarbonamide were used as foaming agents was cut into a square having a side of 300 mm. Thus, a degradable filter having a good appearance was obtained.
Table 1 shows the test results of the obtained degradable filters.

Comparative Example 1 A square filter having a good appearance and a thickness of 20 mm per side of 300 mm was obtained in the same manner as in Example 4 except that polyethylene was used instead of polylactic acid. Temperature condition is supply zone 1
20 ° C, plasticizing zone 130 ° C, melting zone 130 ° C,
The die temperature was 120 to 135 ° C. Table 1 shows the test results of the obtained filters.

Comparative Example 2 The same method as in Example 1 was used except that polycaprolactone was used instead of polylactic acid.
A square filter was obtained. Temperature conditions are: supply zone 100 ° C, plasticizing zone 100 ° C, melting zone 90 ° C,
The die temperature was 80 to 100 ° C. Table 1 shows the test results of the obtained filters.

[0037]

[Table 1]

The decomposable filters containing polylactic acid as a main component obtained in Examples 1 to 5 exhibit a particle collection rate and pressure loss that can sufficiently remove dust particles, and have excellent mold resistance. It has been found that it is hygienic because of having compost, and that composting is performed at a sufficient speed in a biodegradability test in compost. The polyethylene filter obtained in Comparative Example 1 showed a sufficient particle collection rate and pressure loss, but did not decompose at all in the compost. The filter made of polycaprolactone obtained in Comparative Example 2 was decomposed by composting in compost, and showed an effective particle collection rate and pressure loss as a filter, but had no mold resistance at all. .

[0039]

The degradable filter of the present invention uses a foam containing polylactic acid as a main component, and has a practical use such as a particle collection rate, a pressure loss and a mold resistance similar to those of conventional filters made of polyethylene or the like. Can have performance. In addition, the decomposable filter of the present invention is made of polylactic acid resin as a main material, so that it can be easily decomposed by compost, and can be used in an environment that solves the problem of garbage disposal of filters made of polyethylene and polyurethane which are currently a problem. It is a very gentle degradable filter.

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Claims (1)

[Claims] 1. A decomposable filter comprising a foam containing polylactic acid as a main component.