KR19990008580A - Porous Polyurethane Foam for Wastewater Treatment - Google Patents

Abstract

The present invention relates to a porous polyurethane foam for waste water treatment, and more particularly, a polyol compound of polytetramethylene glycol, polypropylene glycol and an aromatic diisocyanate compound as main components, together with a silicone foam stabilizer, tin catalyst, and amine catalyst. And porous polyurethane for wastewater treatment, which is manufactured to have excellent durability to decompose organic matter without hydrolysis even when used as a carrier of microorganisms as well as excellent mechanical properties such as abrasion resistance during long-term flow in wastewater treatment aeration tank by foaming water. It's about a form.

Description

Porous Polyurethane Foam for Wastewater Treatment

The present invention relates to a porous polyurethane foam for waste water treatment, and more particularly, a polyol compound of polytetramethylene glycol, polypropylene glycol and an aromatic diisocyanate compound as main components, together with a silicone foam stabilizer, tin catalyst, and amine catalyst. And porous polyurethane for wastewater treatment, which is manufactured to have excellent durability to decompose organic matter without hydrolysis even when used as a carrier of microorganisms as well as excellent mechanical properties such as abrasion resistance during long-term flow in wastewater treatment aeration tank by foaming water. It's about a form.

Recently, environmental preservation has emerged as the biggest social problem. Especially, in the narrow country such as Korea, there is an urgent need for the development of technology to efficiently treat various wastewaters from domestic sewage and industrial plants, which are the main causes of environmental pollution. Most environmental engineering firms are trying to improve wastewater treatment capacity by efficiently utilizing existing facilities without applying additional new facilities by applying biological treatment method using microorganisms in wastewater treatment.

Biological treatment using microorganisms is a method of treating wastewater using physiological phenomena of microorganisms contained in activated sludge, and is known to be more economical and reliable than conventional physical and chemical methods. Carriers used to support microorganisms in biological wastewater treatment methods require excellent physical properties such as abrasion resistance because they flow with the flow of fluid in the aeration tank of a wastewater treatment facility. Since it is decomposed, it must have acid resistance, alkali resistance and hydrolysis resistance. Among various carriers satisfying the above conditions, polyurethane foam has been widely used as a wastewater treatment carrier because it is chemically and mechanically stable and inexpensive, and various studies have been developed.

For example, in a fluidized bed biofilm treatment [water and wastewater 1990, Vol. 32 No. 5] using a polyurethane foam in Japan, a polyurethane foam having a continuous bubble type having a porosity of 95% or more based on polyether as a base material (Everfoam B ™, manufactured by Bridgestone) was used as a microbial carrier, but various physical properties such as wear resistance were lowered.

Indeed, Linde co., A German environmental engineering company, uses a polyurethane carrier made of polypropylene glycol as a polyol component for wastewater treatment. The polyurethane carrier has good physical properties and abrasion resistance, but has a high economical cost because the product price is very high due to high manufacturing technology transfer costs.

In the present invention, efforts have been made to solve mechanical problems such as high cost and wear resistance of polyurethane foam. As a result, as a polyol compound, a new component which has not been used in the preparation of microbial carriers so far is used, and in the reaction of the polyol compound and the aromatic diisocyanate compound, a foaming reaction is performed by using a silicon foam stabilizer, tin catalyst, amine catalyst and water together The present invention has been completed by making porous polyurethane foam.

Therefore, the present invention improves various properties such as abrasion resistance, tensile strength, and does not wear in the aeration tank of the wastewater treatment plant, and physically bursts the pores to maximize the porosity and uniform the size of the pupils to increase the microbial loading rate, thereby improving wastewater treatment efficiency. It is an object of the present invention to provide a polyurethane foam for microbial carrier that can be increased.

Figure 1a is a photomicrograph before the wastewater treatment aeration tank of the conventional polyester polyurethane foam, Figure 1b is a photomicrograph three weeks after the wastewater treatment aeration tank,

Figure 2 is a micrograph two weeks after the input of the wastewater treatment aeration tank of the conventional polyether foam,

Figure 3 is a micrograph after 4 months of the waste water treatment aeration tank of the porous polyurethane foam of the present invention.

The present invention is a porous polyurethane foam prepared by using a polyol compound and an aromatic diisocyanate compound as a main component, and foaming reaction with other additives, wherein the polyol compound is polytetramethylene glycol, polypropylene glycol, or a mixture thereof. As other additives, for wastewater treatment, 0.85 to 1.00 parts by weight of a silicon foam stabilizer, 0.25 to 0.35 parts by weight of tin catalyst, 0.25 to 0.40 parts by weight of amine catalyst and 3.2 to 4.5 parts by weight of water are added to 100 parts by weight of the polyol compound. It is characterized by a method for producing a porous polyurethane foam.

Referring to the present invention in more detail as follows.

The porous polyurethane foam of the present invention uses a relatively inexpensive polytetramethylene glycol (hereinafter referred to as PTMG), polypropylene glycol (hereinafter referred to as PPG) or a mixture thereof as a polyol compound. When the diisocyanate compound is reacted, it is foamed together with the silicon foam stabilizer, tin catalyst, amine catalyst, and water, so it has excellent physical properties such as abrasion resistance and tensile strength, uniform pore size, and high porosity, thereby increasing the amount of microorganisms to improve wastewater treatment efficiency. Since it is high, it is useful as a microbial carrier for wastewater treatment.

Referring to the manufacturing process of the porous polyurethane foam according to the present invention in more detail.

The first process is a process of adding a silicon foam stabilizer, tin catalyst, amine catalyst and water to the polyol compound and mixing the mixture at medium temperature at 700 to 1200 rpm at room temperature to sufficiently stir it. Considering that the melting point of PTMG is in the range of 22 to 25 ° C, the mixing temperature is preferably maintained at 26 ° C or more.

PTMG as a polyol compound, which is characteristically used in the present invention, has a low glass transition temperature (T _g : -100 ° C) inherent in elongation, abrasion resistance, hydrolysis resistance, and the like. The physical properties of the polyurethane produced by using it alone show much improved results. Therefore, the polyurethane of the present invention will have a soft property, high elasticity and excellent mechanical properties. In the present invention, PTMG can be used alone as a polyol compound, but it is particularly good in that it is economically inexpensive to use the product with PPG, and PPG 0 to 50% by weight relative to 50 to 100% by weight of PTMG. When the physical properties of the polyurethane foam is increased and can be produced a flexible polyurethane foam. However, when the content of PTMG is less than 50% by weight, the softness of the foam is maintained, but wear resistance and mechanical properties are inferior.

In addition, the silicon-based foam stabilizer is to ensure the stability and manufacture of large cells (cell) and to control the opening and the pore size of the cell membrane, which is 0.85 ~ 1.00 parts by weight based on 100 parts by weight of the polyol compound desirable. The tin catalyst is a component added to promote the resinization by activating the polyurethane structure according to the foaming step in the reaction between the isocyanate and the polyol, which is preferably 0.25 to 0.35 parts by weight based on 100 parts by weight of the polyol compound. . The amine catalyst is a component added to promote the reaction, and it is preferable to use 0.25 to 0.40 parts by weight based on 100 parts by weight of the polyol compound. Water is used as a blowing agent and the density of the polyurethane is changed according to the amount of use thereof, and preferably the polyurethane density is adjusted in the range of 36 to 45 kg / m ³ . For this purpose, the water is preferably used 3.2 to 4.5 parts by weight based on 100 parts by weight of the polyol compound.

The second process is a process for producing the porous polyurethane foam of the present invention by mixing the aromatic diisocyanate compound in the mixture of the polyol compound and the additive and then foaming reaction.

30-40 weight part of aromatic diisocyanate compounds are prepared with respect to 100 weight part of polyol compounds, and it stirs at 3000-6000 rpm so that ratio of OH / NCO may be 0.95-1.05. The aromatic diisocyanate compound that can be used in the present invention can be used as long as it is conventionally used in the production of polyurethane, in particular, toluene diisocyanate (hereinafter referred to as "polyol compound"), which can control the density of polyurethane foam low in the reaction with PTMG and PPG. , TDI).

In addition, the polyurethane production method using the raw material is a one-shot method in which each raw material is introduced into the mixing chamber of the foaming machine by a separate line and mixed foamed by a continuous method. Bar, it also has the characteristics to minimize the manufacturing cost by simplifying the process of manufacturing polyurethane foam.

The polyurethane foam thus prepared is mixed with a natural gas and oxygen within an explosion limit, and ignited to produce a porosity of 95% or more by physically popping pores using a method of destroying the membrane by the impact. Unlike the conventional polyurethane polyether foam, such a manufacturing method has an advantage that the micropore is easily attached and the specific surface area can be increased by opening the pores of the net foam almost 100%.

Polyurethane foam of the present invention as described above not only has excellent abrasion resistance and tensile strength, the pore size of the foam is uniform and very large porosity is very useful as a microbial carrier for biological treatment of living and municipal sewage, and industrial wastewater .

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Examples 1-3 and Comparative Examples 1-2

The polyol compound was added to a mixed stirring vessel at 26 ° C., and a silicon foam stabilizer, tin catalyst, amine catalyst and water were added to the compositions shown in Table 1 below, followed by stirring at 1000 rpm.

Toluene diisocyanate (TDI-80; manufactured by Fine Chemicals Co., Ltd.) was added to the mixture while maintaining the composition in the following Table 1 and rapidly stirring at 4000 rpm for 6 seconds at an injection rate in an open box and a continuous conveyor line. And foamed to explode pores to prepare polyurethane foam.

Raw material name Example Comparative example One 2 3 One 2 Polyol PTMG-2000 ⁽¹⁾ 50 g 70 g 100 g - - PPG-5000 ⁽²⁾ 50 g 30 g 0g - - GP-3000 ⁽³⁾ - - - 100 - PP-2000 ⁽⁴⁾ - - - - 100 Defoamer L-580 ⁽⁴⁾ 0.5g 0.8 g 1.0 g 1.0 1.5 L-45 ⁽⁵⁾ 0.2 g 0.3 g 0.5g - - Tin catalyst T-9 ⁽⁶⁾ 0.2 g 0.3 g 0.4g 0.2 0.2 Amine catalyst Dabco-33LV ⁽⁷⁾ 0.2 g 0.4g 0.5g 0.3 0.3 blowing agent water 3.0 g 3.5 g 4.0g 3.0 3.0 TDI-80 30 g 35 g 40 g 45 45 OH / NCO ratio 1.05 1.0 0.95 1.05 1.05 (1) PTMG-2000: Polytetramethylene glycol, product of Hodogaya, Japan (2) PPG-5000: Polypropylene glycol, homochemical product (3) GP-3000: Polyoxypropylated glycerin, product of Korea Polyol Co., Ltd. (4) PP-2000: Polyoxypropylene Glycol, Korea Polyol Co., Ltd. (5) L-45: US OSi Specialties Co., Ltd. (6) L-580: US OSi Specialties Co., Ltd. (7) T-9 (Tin Catalyst): USA Air Product Chemical Company (8) Dabco-33LV (Amine Catalyst): US Air product Chemical Company (9) TDI-80 (toluene diisocyanate): Korea Fine Chemicals

Experimental Example

The physical properties of Examples 1 to 3, Comparative Examples 1 to 2, and conventional foam products were measured by the following methods, and are shown in Table 2 below.

(1) Density measurement: Physical property test It measured according to JIS-K-6401 Clause 5.3.

(2) Tensile strength measurement: Measured according to the property test standard JIS-K-6401 Clause 5.3.

(3) Elongation measurement: measured according to the physical property test standard JIS-K-6401 Clause 5.3.

(4) Tear strength measurement: Measured according to the physical property test standard JIS-K-6401 Clause 5.3.

(5) Abrasion resistance measurement: Polyurethane foam was cut into 12 × 12 × 12mm square size and 20 volume% of the total capacity of the waste water treatment acrylic aeration tank was used to decompose organic matter in the waste water by attaching microorganisms to the carrier. In order to observe the wastewater treatment efficiency characteristics, the polyurethane foam administered in the wastewater treatment aeration tank for 4 months was continuously flowed by an air blower.

division Example Comparative example One 2 3 One 2 Polyester foam ^(a) Polyether foam ^(b) Density (kg / m ³ ) 35 35 40 35 35 35 35 Tensile Strength (kg / cm ² ) 1.6 1.7 1.7 1.12 1.10 1.4 1.03 % Elongation 455 450 450 205 305 366 180 Tear strength (kg / cm) 1.25 1.3 1.35 0.85 1.09 1.2 0.7 Porosity (%) 95 95 95 95 95 95 95 Wear No wear No wear No wear 10% wear on corner after 2 weeks 10% wear on corner after 2 weeks Hydrolysis occurred after 3 weeks of testing 10% wear on corner after 2 weeks Weight change ⁽¹⁾ Almost unchanged Almost unchanged Almost unchanged 10% decrease after 2 weeks 10% decrease after 2 weeks 30% reduction after 2 weeks of testing 10% reduction after 2 weeks of testing (1) Weighing 100 weights of polyurethane foams of 12 × 12 × 12mm size used as microbial carrier by measuring weight change before and after aeration tank (a) Polyester foam: Product of Joyce, Australia : Flexible polyurethane foam Grade S30 / 30 (b) Polyether foam: KOLIX GP-3000

As observed in Table 2, the polyurethane foam of the present invention is excellent in wear resistance and superior to the physical properties of the polyether foam (manufactured by Korea Polyol Co., Ltd.) which is commonly applied for wastewater treatment. In the case of the polyester foam (manufactured by Joyce, Australia), the weight was reduced by 30% in two weeks after the test, and even before the injection into the wastewater treatment aeration tank (see FIG. 1A) and three weeks after the introduction (see FIG. 1B) also in the observation of wear under the microscope. When comparing the), it can be seen that the wear degree due to hydrolysis is severe. In the case of the polyether foam (manufactured by Korea Polyol Co., Ltd.), it was also seen that the wear was severely shown at the corners of the polyurethane foam in two weeks (see FIG. 2). However, the porous polyurethane foam according to the present invention was confirmed that excellent wear resistance hardly showed abrasion even after 4 months into the waste water treatment aeration tank (see FIG. 3).

Therefore, it can be seen that the porous polyurethane foam of the present invention can be continuously used and reused for wastewater treatment microbial carriers.

As described above, the polyurethane foam produced by the manufacturing method of the present invention not only has excellent wear resistance and tensile strength, but also can simplify the processing and manufacturing process of the foam, thereby minimizing the manufacturing cost. Used as a microbial carrier for treatment, it is very useful for increasing wastewater treatment efficiency.

Claims (2)

In the porous polyurethane foam prepared by using a polyol compound and an aromatic diisocyanate compound as a main component, and foaming reaction with other additives, As the polyol compound, polytetramethylene glycol, polypropylene glycol, or a mixture thereof is used, and as other additives, 0.85 to 1.00 parts by weight of a silicon foam stabilizer, 0.25 to 0.35 parts by weight of tin catalyst, and amine based on 100 parts by weight of the polyol compound. A porous polyurethane foam for wastewater treatment, wherein 0.25 to 0.40 parts by weight of catalyst and 3.2 to 4.5 parts by weight of water are added. According to claim 1, wherein the polyol compound polytetramethylene glycol and polypropylene glycol 50 to 100% by weight: porous polyurethane foam for wastewater treatment, characterized in that consisting of 0 to 50% by weight.