JP2003001627A - Method for manufacture of additive-containing prefoamed resin particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacture of an additive-containing prefoamed resin particle which can contain almost uniformly a plastic additive at a low cost and can obtain a foamed resin molded body excellent in mechanical strength. SOLUTION: A foaming resin particle 1 is heated while it is stirred with a stirring blade 45 in a prefoaming machine 4. After the foaming resin particle 1 starts foaming, the prefoamed resin particle containing the plastic additive is manufactured by adding the plastic additive 2 to the foaming resin particle 2 which is foaming.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing pre-expanded resin particles containing an additive, which has properties such as insect repellent, ant repellent, heat resistant, fire resistant, flame retardant, coloring, antistatic, conductive, and improved moldability.

[0002]

2. Description of the Related Art Conventionally, in order to include properties such as insect repellent and ant repellency in a foamed resin molded product, it has been practiced to incorporate a plastic additive exhibiting these properties into the foamed resin molded product. For example, Japanese Patent Application Laid-Open No. 3-202528 discloses a technique of incorporating an anti-termite agent into a foamed resin molded body. As a method for imparting such desired properties to the foamed resin molded body, a method of adding a plastic additive imparting a desired effect at the time of polymerization, a method of adding at the time of molding the foamed resin molded body, or a method of directly adding to the foamed resin molded body The method of addition and the like are generally known.

As the above method, Japanese Patent Laid-Open No. 3-202
As disclosed in Japanese Patent No. 528, there is known a method of pre-foaming after mixing the expandable resin particles with an anti-termite agent before foaming. Further, as the above method, Japanese Patent Laid-Open No. 3-2
As disclosed in Japanese Patent No. 02528, there are known a method of immersing a foamed resin molded product in a solution for treating an anti-termite agent, a method of coating a surface of the foamed resin molded product with an anti-termite agent, and the like.

[0004]

[Problems to be solved]

However, the above-mentioned method of adding at the time of polymerization requires a huge amount of equipment cost, resulting in a large production cost and is not economical. Further, in this method, it is necessary to add a large amount of a plastic additive in order to exhibit good properties, and there is a problem in that the mechanical strength of the foamed resin molded product obtained is remarkably reduced.

Further, the above-mentioned method is not economical because it requires a dedicated facility for applying the plastic additive to the foamed resin molded body, which increases the manufacturing cost.

[0007] In the above method, when adding the plastic additive, it is only necessary to mix them, so that no special equipment is required. Therefore, there is a possibility that a foamed resin molding containing the additive can be manufactured at low cost. However,
In this method, since the expandable resin particles are made to contain the plastic additive and then pre-expanded, the plastic additive may be locally unevenly distributed in the pre-expanded resin particles. Therefore, there is a problem in that it is not possible to obtain a foamed resin molded product that uniformly contains the desired properties, and variations in mechanical strength occur.

Further, according to this method, the expandable resin particles are coagulated with each other to form an agglomerate during the pre-expansion, and normal pre-expanded resin particles may not be obtained.

The present invention has been made in view of the above conventional problems, and it is possible to obtain a foamed resin molded article which can contain a plastic additive substantially uniformly at low cost and has excellent mechanical strength. It is intended to provide a method for producing pre-expanded resin particles containing an additive, which is capable of producing.

[0010]

According to the present invention, a foaming resin particle is heated in a pre-foaming machine while being stirred, and after the foaming resin particle starts foaming, a plastic additive is added to the foaming resin particle that is foaming. Is added to produce pre-expanded resin particles containing the plastic additive, which is a method for producing pre-expanded resin particles containing additive (claim 1).

Next, the function and effect of the present invention will be described.
In the present invention, a plastic additive is added to the expandable resin particles that are being foamed in the pre-expanding machine, and the plastic additive is contained in the expandable resin particles to obtain desired properties such as insect repellent and termite repellent. A pre-expanded resin particle containing is produced. That is, when applying the additive to the expandable resin particles, it is not necessary to use special equipment such as the dipping device as described above, and use the same equipment as the process for producing the pre-expanded resin particles. You can Therefore, according to the present invention, the additive-containing pre-expanded resin particles can be produced at low cost.

Further, since the plastic additive is added to the foaming resin particles in a foaming state, the plastic additive is contained substantially uniformly over the entire surface of the foaming resin particles being foamed. be able to. Moreover, since the inside of the pre-foaming machine is heated and stirred by steam etc., the above plastic additive is
It diffuses throughout the pre-foaming machine and makes good contact with the expandable resin particles. Therefore, the plastic additive can be contained substantially uniformly over the entire surface of the expandable resin particles without causing local uneven distribution.

The expandable resin particles are agitated while the additive is applied. Therefore, the foaming resin particles that are foaming do not coagulate with each other to form a lump. Therefore, additive-containing pre-expanded resin particles having a substantially uniform size can be manufactured. Therefore, when a foamed resin molded article is produced using the additive-containing pre-expanded resin particles produced according to the present invention, it contains desired properties such as insect repellent and termite proof and is excellent in mechanical strength. It is possible to obtain a foamed resin molded body.

Therefore, according to the present invention, a plastic additive can be contained substantially uniformly at low cost, and a foamed resin molded article having excellent mechanical strength can be obtained. A method for producing resin particles can be provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, examples of the expandable resin particles include polystyrene-based expandable resin particles,
Polyethylene foamable resin particles, polypropylene foamable resin particles, polymethylmethacrylate foamable resin particles, urethane foamable resin particles, isocyanurate foamable resin particles, melamine foamable resin particles, phenolic foamability Resin particles and copolymer foamable resin particles thereof can be used.

The pre-foaming machine for producing the above-mentioned additive-containing pre-foamed resin particles is, for example, a normal pressure batch pre-foaming machine, a pressure batch pre-foaming machine, a continuous pre-foaming machine, a warm air batch pre-foaming machine. A foaming machine or the like can be used. These are equipped with stirrers. Preferred are atmospheric and pressure batch type pre-foaming machines.

The above plastic additives include insect repellent,
There are some properties that give pre-expanded resin particles properties such as ant-proofing, heat resistance, fire resistance, flame retardancy, coloring, antistatic, conductivity, and shortening the cooling time in the molding process, reducing water content, and improving moldability such as filling property. .

For example, insect repellents, insect repellents containing ant repellents, and ant repellent plastic additives include pyrethroids such as silafluofene, etofenprok, flufenproc, permethrin, bifenthrin, tralomethrin, chlorpyrifos, phoxim, Pyridaphenthion, tetrachlorovinphos, fenitrothion,
Organophosphorus drugs such as propetanphos, Fenobucarb,
Carbamate drugs such as carbamic acid ester, chloropyridylmethyl group-containing drugs such as fipronil, acetamiprid, and imidacloprid, chromium-copper-arsenic compound-based drugs, chlornaphthalene-based drugs, sodium arsenate, lead arsenate, barium arsenate acid. Such as arsenic compounds, lead fluoride, barium fluoride, fluorinated compounds such as sodium silicofluoride, copper compounds, dinitroorthocresol, tributyltin oxide, boron compounds such as borate, titanium compounds such as titanium oxide, hinokitiol, creo Sort oil, triazine-based agents, metal naphthenates such as copper naphthenate, organotin compounds, inorganic fluorides of phenols,
There is a mixture of P-chlorometa-xylil and 3,6 dichloropyritazine. Further, it may have any action such as a contact poison, a food poison, a respiratory poison, and a repellent termite.

Further, the plastic additives such as insect repellents and termite repellents may be used not only in one kind but in two or more kinds. When the additive-containing foamed resin molded product is used as a heat insulating material or heat insulating material for buildings, it is preferable to use borate, pyrethroid-like and systemic agents, imidacloprid, etc. as insect repellents and termites. Since these have low toxicity, they are suitable for buildings.

Next, a preferred embodiment of the present invention will be described. It is preferable that the plastic additive is added after the expandable resin particles have been expanded to an expansion ratio of 1.8 times or more (claim 2). The expandable resin particles have a volume of 1.8 times or more as compared with the volume before expansion, that is, an expansion ratio of 1.
When foaming 8 times or more, a dense layer is formed at the bottom of the pre-foaming machine. Since the plastic additive is added to this state, it is possible to prevent the plastic additive from adhering to the bottom of the pre-foaming machine or flowing out to the drain line. Therefore, the plastic additive can be efficiently added to the expandable resin particles.

Further, it is preferable that the plastic additive is continuously added (claim 3). In this case, since the plastic additive is continuously applied to the surface of the expandable resin particles that are foaming, the plastic additive can be contained substantially uniformly over the entire surface of the pre-expanded resin particles. .

Next, the expandable resin particles are preferably polystyrene-based expanded resin (claim 4). In this case, in particular, a foamed resin molded product having high mechanical strength and high heat insulation can be manufactured.

Next, the plastic additive is one or two selected from insect repellents, termite repellents, heat resistance agents, fire retardants, flame retardants, colorants, antistatic agents, conductive agents and moldability improving agents.
It is preferably at least one species (claim 5). In this case, the properties depending on the plastic additive can be imparted to the additive-containing pre-expanded resin particles.

[0024]

Example 1 In this example, as shown in FIG. 1, the expandable resin particles 1 were heated in a pre-expanding machine while being stirred, and after the expandable resin particles 1 started foaming. An additive-containing pre-expanded resin particle 3 containing the plastic additive was produced by adding the plastic additive 2 to the foaming resin particle 1 which is expanding.
In addition, a foamed resin molded body was produced using the additive-containing pre-foamed resin particles 3, and the mechanical strength of the foamed resin molded body was measured, and a feeding damage test using a termite was performed. Hereinafter, this example will be described in detail with reference to FIGS.

First, as shown in FIG. 1, 600 g of polystyrene-based expandable resin particles 1 (manufactured by Mitsubishi Foam Plastic Co., Ltd., Styropol, JF200) was added to 600 g of a foaming capacity, and a normal pressure batch type pre-foaming machine equipped with a stirring blade. Put in 4. Then, while stirring the expandable resin particles 1 inside the pre-foaming machine 4 with the stirring blade 45 provided in the pre-foaming machine 4, steam with a pressure of 98 kPa is introduced from the steam generator 5, Pre-foaming started. Next, FIG.
As shown in (1), about 10 seconds after starting the introduction of steam, the termite proofing agent imidacloprid, which was put in the injection tank 41 as the plastic additive 2, was added. Approximately 10 seconds after starting the introduction of steam, the expandable resin particles 1 inside the pre-expanding machine are whitened and form an overcrowded layer at the bottom of the pre-expanding machine. The expansion ratio was about 2 times.

Then, the foaming of the expandable resin particles 1 was further continued until the level of 30 L was reached, and the introduction of steam was stopped. Then, from the compressed air tank 6 to 48 kPa
The compressed air of (1) was introduced into the pre-expanding machine 4 for 10 minutes to dry the pre-expanded resin particles containing the additive of 50 times expansion containing imidacloprid.

In FIGS. 2 and 3, reference numeral 51 is a pressure gauge, 6 is a compressed air tank for storing air for drying the additive-containing pre-expanded resin particles in the pre-expanding machine 4,
46 is a motor.

Next, the additive-containing pre-expanded resin particles were sieved with a wire mesh having a mesh size of 10 mm to obtain additive-containing pre-expanded resin particles having a substantially uniform size. At this time, the amount of lumps remaining on the wire mesh was measured in order to investigate the amount of lumps contained in the additive-containing polystyrene pre-expanded resin particles. The results are shown in Table 1.

Further, VS-500 was prepared by adding the additive-containing pre-expanded resin particles having a substantially uniform size from which the above-mentioned lumps were removed.
Introduced into a mold molding machine (manufactured by Daicel Industries), molding,
A plate-shaped foamed resin molded body containing imidacloprid having a size of 30 cm in length × 20 cm in width × 2.5 cm in thickness was obtained.

From the above foamed resin molded product, length 10 cm × width 1
A sample having a size of 0 cm and a thickness of 2.5 cm was cut out to obtain a 5% compressive strength test sample. Similarly, a sample having a size of 7.5 cm in length × 30 cm in width × 2.5 cm in thickness was cut out to obtain a bending strength test sample and a density measurement sample. Next, using each of the above samples, J
According to the measuring method specified in IS-A-9511, 5%
A compressive strength test, a bending strength test and a density measurement were carried out.
The results are shown in Table 1.

From the foamed resin molding containing imidacloprid, a length of 10 cm × width of 10 cm × thickness of 2.5 c
A sample with a size of m was cut out and a termite feeding test was performed. That is, first, the weight (B0) of the termite feeding damage test sample was measured with a weighing machine. This sample was placed in a glass lidded container having a diameter of 20 cm and a height of 5 cm, and 150 termite termite workers and 15 soldier ants were placed therein, saturated saline was added thereto, and the lid was closed.

Next, the glass container was placed at 25 ° C. ± 2 ° C.
Installed in a constant temperature room with a humidity of 80% ± 10%, and under full dark conditions 3
Left for a week. The sample weight (B1) after standing was measured with a weighing machine. And the reduction amount (B2 = B0-B1) and the reduction rate (10
0 * (B0-B1) / B0) was calculated. Moreover, the feeding damage situation was observed. The results are shown in Tables 2 and 3.

Each of the above measurements was conducted using 600 g of expandable resin particles.
On the other hand, the additive-containing pre-expanded resin particles (Table 1) containing 0.1, 0.2, or 0.3 parts by weight of imidacloprid were used.

(Comparative Example 1) In this example, the expandable resin particles were pre-expanded with a plastic additive before being pre-expanded, charged into a pre-expanding machine, foamed while being stirred and heated, and the additive-containing pre-expanded resin was added. Expanded resin particles were produced. In addition, Example 1
Similarly to the above, using the additive-containing pre-expanded resin particles,
A foamed resin molded body was prepared, and its mechanical strength was measured, and a feeding damage test with termites was performed. Hereinafter, the production of the additive-containing pre-expanded resin particles for the comparative example will be described in detail with reference to FIG.

First, polystyrene-based expandable resin particles 1
(Mitsubishi Foam Plastic Co., Ltd., Styropol, JF200) 600 g was put into the polyethylene bag 7. Then, the termite-preventing agent imidacloprid was added as a plastic additive 2 into the bag 7. continue,
The bag 7 was shaken up and down to mix the expandable resin particles 1 and the termiticide imidacloprid to obtain expandable resin particles containing imidacloprid.

Next, in the same manner as in Example 1, the expandable resin particles were put into an atmospheric pressure batch type pre-expanding machine. Introduce steam with a pressure of 98 kPa and stir 30L
Bubbling to the level of and stopping steam. continue,
Compressed air of 48 kPa was introduced into the pre-expanding machine for 10 minutes to dry the pre-expanded resin particles containing the additive of 50 times expansion containing imidacloprid.

Next, the amount of lumps was measured in the same manner as in Example 1 using the above-mentioned additive-containing pre-expanded resin particles. Further, a foamed resin molded article was produced in the same manner as in Example 1 using the above additive-containing pre-expanded resin particles, and the same measurement as in Example 1 was performed. The results are shown in Tables 1 to 3 above.

In each of the above-mentioned measurements, as in Example 1, 600 g of expandable resin particles were mixed with imidacloprid of 0.
Pre-expanded resin particles containing an additive added with 1, 0.2, or 0.3 parts by weight (Table 1).

Comparative Example 2 In this example, pre-expanded resin particles containing no plastic additive are produced. Further, in the same manner as in Example 1, a foamed resin molded body was prepared using the pre-foamed resin particles, and the mechanical strength of the foamed resin molded body was measured, and the feeding damage test by the termites was performed. .

The present example will be described in detail below. First, expandable polystyrene resin particles (Mitsubishi Foam Plastic Co., Ltd., Styropol, JF200)
600 g was put into an atmospheric pressure batch pre-foaming machine with a foaming capacity of 30 L and equipped with a stirring blade. Introduced steam with pressure of 98 kPa,
In the same manner as in Example 1, 50-fold expanded pre-expanded resin particles were obtained.

Then, using the above-mentioned pre-expanded resin particles, the amount of lumps mixed in the pre-expanded resin particles was measured in the same manner as in Example 1. Further, a foamed resin molded body was produced using the above-mentioned pre-foamed resin particles, and the same measurement as in Example 1 was performed. The results are shown in Tables 1 to 3 above.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

[Table 3]

As can be seen from Table 1, the additive-containing pre-expanded resin particles (Example 1) obtained according to the present invention showed almost no lumps during pre-expansion and contained the plastic additive. It was about the same as the unexpanded resin particles (Comparative Example 2). Further, the foamed resin molded product obtained by the present invention had excellent mechanical strength of about 5% in compressive strength and bending strength, which were almost the same as those of Comparative Example 2.

On the other hand, in the additive-containing pre-expanded resin particles (Comparative Example 1) produced by pre-expanding the plastic additive in the expandable resin particles, a very large amount of lumps were generated. ， In addition, the mechanical strength was also reduced. Further, comparing the content of imidacloprid contained in the additive-containing pre-expanded resin particles (Example 1) obtained according to the present invention with that of Comparative Example 1, the additive-containing pre-expanded foam obtained according to the present invention was compared. It was found that the content of resin particles was higher.

Further, as is known from Tables 2 and 3, the additive-containing foamed resin molded product (Example 1) obtained according to the present invention has a low rate of reduction in food damage and a high termite resistance. I found out that On the other hand, the additive-containing foamed resin molded article produced in Comparative Example 1 does not have sufficient anti-termite property when the content of the plastic additive is small.

Further, in Comparative Example 1, when the content of the plastic additive is increased, the termite-proof property is exhibited, while on the other hand, as is known from Table 1, the mechanical strength of the foamed resin molding is lowered. is doing. On the other hand, the additive-containing foamed resin molded product obtained according to the present invention has a sufficient termite-proof property and high mechanical strength even when the content of the additive is low.

In the termite feeding damage test,
When the feeding damage situation of Example 1 and Comparative Example 1 were compared and observed,
It was observed that the feeding damage in Comparative Example 1 occurred locally. That is, it is considered that the foamed resin molded product obtained by the method of Comparative Example 1 had a portion containing almost no plastic additive, and this portion was damaged by the termites. On the other hand, in the foamed resin molded product (Example 1) of the present invention, since the plastic additive is uniformly contained, such food damage is hardly observed.

Further, as shown in Table 3, the mortality of the termites in the termite feeding damage test was examined, and in Example 1, 90% to 100% of them died. On the other hand, in Comparative Example 2, it is zero. Further, in Comparative Example 1, when the added amount of imidacloprid is 0.1 part by weight, it is as low as 30%. This is probably because the plastic additive was only partially contained.

[Brief description of drawings]

FIG. 1 is an explanatory view of a method for producing additive-containing pre-expanded resin particles according to Example 1.

FIG. 2 is an explanatory view of a pre-foaming machine before pre-foaming according to the first embodiment.

FIG. 3 is an explanatory diagram of the pre-foaming machine according to the first embodiment in which a plastic additive is added while being foamed by heating.

FIG. 4 is an explanatory view of a method for producing expandable resin particles containing a plastic additive according to Comparative Example 1.

[Explanation of symbols]

1. ． ． Expandable resin particles, 2. ． ． Plastic additives, 3. ． ． Pre-expanded resin particles containing additives, 4. ． ． Pre-foaming machine, 45. ． ． Stirring blade

Continued front page    F-term (reference) 4F074 AA32 AG06 AG07 AG08 AG10                       AG12 CA38 CC47 DA02                 4F201 AA13 AB01 AB05 AB07 AB09                       AB12 AB13 AC01 AG20 AR11                       AR20 BA02 BC01 BC12 BC19                       BC37 BD02 BL42 BL43 BL48                       BQ47

Claims (5)

[Claims] 1. An expandable resin particle is heated in a pre-expanding machine while being stirred, and after the expandable resin particle starts to expand, a plastic additive is added to the expandable expandable resin particle. A method for producing pre-expanded resin particles containing an additive, comprising producing pre-expanded resin particles containing the plastic additive. 2. The method for producing pre-expanded resin particles containing an additive according to claim 1, wherein the plastic additive is added after the expandable resin particles have been expanded to an expansion ratio of 1.8 times or more. . 3. The method for producing pre-expanded resin particles containing an additive according to claim 1 or 2, wherein the plastic additive is continuously added. 4. The method according to claim 1, wherein
The method for producing an additive-containing pre-expanded resin particle, wherein the expandable resin particle is a polystyrene-based expanded resin. 5. The plastic additive according to any one of claims 1 to 4, wherein the plastic additive is an insect repellent, an anti-termite agent, a heat-resistant agent, a fire retardant, a flame retardant, a colorant, an antistatic agent, a conductive agent, or a molding agent. A method for producing additive-containing pre-expanded resin particles, which is one or more selected from the property improving agents.