WO2018143899A1

WO2018143899A1 - Porosity control process of modified natural rubber foam and its application for oil sorption

Info

Publication number: WO2018143899A1
Application number: PCT/TH2018/000004
Authority: WO
Inventors: Suwadee KONGPARAKUL
Original assignee: Kongparakul Suwadee
Priority date: 2017-02-03
Filing date: 2018-01-31
Publication date: 2018-08-09

Abstract

Process to control pore size of the oil sorbent foam from modified natural rubber and its applications where the pore size can be controlled by agitator speed. The pore size effected to the rate of oil sorption. The density of the foam from this process was in the range of 0.28-0.56g/cm with open pore structure with pore size less than 100 microns.

Description

POROSITY CONTROL PROCESS OF MODIFIED NATURAL RUBBER FOAM AND ITS APPLICATION FOR OIL SORPTION BACKGROUND OF THE INVENTION

1. Science that related to this invention

Chemistry and polymer both are involved in porosity control of modified natural rubber foam and its application for oil sorption.

2. Related History Background of Art and Science.

Oil spilled in the ocean caused by variety of factors for example accidently leakage of oil pipeline under the ocean, shipwrecked, boat collision, and leakage or spilled during oil transfer process. If there is massive amount of oil spilled into the ocean and prolong oil stain without any prevention strategy nor oil management process this will consequently affect the natural resources and also marine ecology. Its will also later effect both economy and sociology of local and country.

Nowadays there are many manage strategies for oil spill in either natural canal, tunnel or event in the ocean. Physical oil spill management strategy including using oil boards to separate and control oil spill area in order to prevent oil stain spread out over the wide area and using oil skimmer machine to collect the oil spill. Burning down process also be used in the case of oil spill exit more than 3 mm layer. Another process is using surfactant substance and chemicals sprayed over the surface of oil spill in order to break down them into the smaller molecule which will naturally degradation. However, this process of using chemical in environment restoration still remain no report of short or long-term effect to the ecology system. As per the study of oil spilled at Mexico Gulf 2 years after the incident shown normal environment at the incident site but there is more collection of carcinogenic substance level in the living organism. This result shown long- term effect of the chemical used in oil spill management process. So that there is development study into oil spill management process that enable environment friendly and has less or none effect to the ecology system neither short or long term.

Using absorbent subjects for oil spill management is the most easy and convenient method, also help to get rid of oil stain in the coastal areas. This method also used to combine with oil board by adding the oil sorption in the general oil board which help to absorb the oil on the surface faster without absorb the mixed of water, with less flammable and can be floated after oil absorption. General absorbent substances are made from synthetic polymers (polymers from oil refinery process) for example polyethylene and polyurethane. It is also including using biomass waste as an absorbent substance for example corn cob (American Patent No: US 3,617,564 and US 5,160,629) wood sliver (American Patent No US 4,959,154). However absorbent substances made from biomass waste absorb both oil and water resulting in less absorb of oil than synthetic polymers.

There are a numbers of synthetic polymers oil absorbent widely used now such polyurethane by Japan Patent No. JP 1997248455 A, JP 1996073556 A, and JP 1996073556 A. As per previously mentioned the process of making this oil absorbent required a chemical content from petrochemical during oil refinery process. The quality of oil absorption will also depend on the type and content of foam. As per American Patent No. US 20110293374 Al, the polyurethane foam density is between 0.070 - 0.300 gm/cm³ and foam porous between 1-20 cells/cm which will allow to absorb oil 2.15 - 4.40 times. Other oil absorption used is made from the mixture of polyethylene and ethylene-alkyl acrylate as per American Patent No. US 8853289 B2 mentioned about the ability to absorb engine oil SAE30 (as per standard viscosity by nation engineer association) which these polymers could absorb oil up to 25 - 30 times.

As per the above-mentioned patents, the use of synthetics polymers in oil absorbent have increased the ability of oil absorption. However, the process of making the absorbent subject required other chemical substance from oil refinery which none reusable resource whereas absorbent substances made from biomass waste has less absorption ability than synthetic polymers. Therefore, a development of modified natural rubber foam oil absorption Thai Petty Patent No. 9980 which explained about the process of making and the use of modified natural rubber foam oil absorption. Not just only its better ability in absorption however it can also be reused more than 30 times and maintain shape after used. By using this absorbent substance in industry has developed the better ability of oil absorption (Thailand Petty Patent No. 12077) and life-long extension quality (Thailand Petty Patent No. 12076). From both development has produced the better modified natural rubber oil absorption with faster absorb ability and with the larger size can be reused more than 100 times when used with strapping machine its will also remain the ability of absorption.

Thailand is well known as one of the leader country for continuously export rubber, and the rubber price has leading the same direction of crude oil price. These will be major fact that the rubber price will gowning up as per demanding use of natural rubber (polymers from rubber trees) and synthetic rubber (polymers from oil refinery process) in most of the industrial. Nowadays, there is no zoning for rubber tree planting for the control supplier purpose to meet with the demanding of the market. So that if there is slowing down number of the rubber demanding from the market and the crude oil price drop then will affect directly to the rubber price. This invent aim directly to increase the value of natural runner and its modified products. The invent also help to encourage Thai local rubber supplier to realize the important of rubber modifying into the variety of products by Thai innovation. It will also help to reduce importing of oil absorption products from oversea where is the same quality products that are made locally and cheaper.

3. Specification and Objective of this invention.

This study related to the control process of porosity of the modified natural rubber foam for oil absorption purpose. Objective of this invention is to control the physical ability of this foam to absorb and separate the oil from the natural water sources by faster absorbing only the oil spilled on the water surface and remain floating on the surface level. Using this modified natural rubber foam oil absorption in the incident of oil spilled will help to reduce the risk of spreading oil strain into ecosystem under water. As if there is the contaminated of oil strain in the water then will resulting in the effects to the ecosystem both short and long-term effects.

4. Completed disclosure invention

Porosity control process of natural rubber foam oil sorption can be prepared by mixing a high ammonia natural rubber latex (with dry rubber content of 60%) with another vulcanizing ingredient as shown in Table 1 by order with agitation speed of 300 - 1 ,200 rpm at 22 - 25°C. The total solid content was controlled in the range of 55 - 59% to produce well-distribution open pore structure. The foam preparation can be prepared in 5 L batch type mixer equipped with two whiskers and stirred for 15-20 min per batch. The mixture was transferred into the mold and left at ambient for 1 h, then steam vulcanized for 20-30 min. Finally, the foam was air dried at 30 - 35°C to obtain modified natural rubber foam with density in the range of 0.28-0.56 g/cm³. TABLE 1 Ingredient of modified natural rubber latex

Component Weight per hundred gram of rubber (phr)

Concentrated rubber latex 100

(with dry rubber content of 57-63 %)

Blowing agent (Potassium oleate) 1.5 - 2.0

Emulsion (Alkyl acrylate) 1.0 - 2.0

Vulcanizing agent (Sulfur) Less than 2.0

Accerelator (Zinc diethyldithiocarbamate) Less than 1.0

Accerelator (Mercaptobenzothiazole) Less than 1.0

Protective agent (Wing stay L) Less than 1.0

Accelerator activators (Zinc oxide) Less than 5.0

Vulcanization accelerators (Diphenylguanidine) Less than 0.7

Gelling agent (Sodium silicofluoride) 0.5 - 1.0

For oil sorption capacity and reusability testing, the oils with various viscosity from 0.65 - 37.0 centistoke were used. A cubic shape foam sample (1.0 cm χ 1.0 cm x 1.0 cm) with approximate weight of 0.1 g was immersed into container which contained 20 - 40 ml of oil and record oil sorption capacity various with time for 0 - 3600 s. The foam was discarded from oil container and removed the excess amount of oil, washed with ethanol, dried and recorded the weight of the foam and at least 3 replications to get the average value. The example of this invention is shown as follow

EXAMPLE 1

The testing for the effect of agitator speed for rubber foam sorbent porosity control to the foam density of modified natural rubber is shown in FIG.1 where the agitation speed was 300 - 1,200 rpm. Low density and small pore size foam from this invention was obtained from high agitator speed process where the foam density was 1.01 g cm³ and 0.31 g cm³ by mixing at 300 rpm and 1,200 rpm, respectively. EXAMPLE 2

For oil sorption test for modified natural rubber foam obtained from the process, two differences viscosity of petroleum-based oil were used for the oil sorption test (0.65 and 37.0 centistoke). The sorption capacity various with time was recorded and illustrated in FIG 2 and FIG.3. The oil sorption rate was depended on oil viscosity and the foam density where the low density foam performed high oil sorption rate of low viscosity oil. The oil sorption capacity of low viscosity oil (0.67 centistoke) was 7-16 g/g within 0 - 60 s and the oil sorption capacity of high viscosity oil (37.0 centistoke) was 2-8 g/g within 30-600 s. In conclusion, high viscosity of petroleum oil performed longer time in sorption process than low viscqsityoil.

EXAMPLE 3

The morphology of modified rubber foam obtained from the process before diesel sorption and after diesel sorption test are illustrated in FIG. 4. The open-cell pore structure with the pore size less than 100 microns was observed and retained the porous structure after oil sorption and retained the absorbed oil within the foam and not sank into the water.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates the effect of agitator speed to foam density FIG. 2 illustrates the sorption rate of engine oil with 0.65 centistoke. FIG. 3 illustrates the sorption rate of engine oil with 37.0 centistoke. FIG. 4A illustrates pore characteristic before diesel sorption. FIG. 4B illustrates pore characteristic after diesel sorption.

5. The Best Invention Method

As described in the Completed disclosure invention topic

6. Application of the invention to industrial, commercial, handicraft or agricultural production.

Industrial, commercial

Claims

What is claimed is:

1. The process to control porosity of the modified natural rubber comprising:

a) Preparation of rubber foam for oil sorbent

i. Mix a concentrated natural rubber latex (60% dry rubber content) with vulcanizing ingredients at agitator speed of 300-1200 rpm at 22-25°C, steam vulcanized for 20-30 min and air dry at 30-35°C.

b) Pore size control

i. A latex compound from step a. and blowing agent was mixing speed in the range of 300 rpm to 1,200 rpm

2. The oil-based absorbent foam obtained by the process of production according to claim 1 comprising

Concentrated rubber latex 100 (phr)

Potassium oleate 1.5 - 2.0 (phr)

Alkyl acrylate emulsion 1.0 - 2.0 (phr)

Sulfur Less than 2.0 (phr)

Zinc diethyldithiocarbamate Less than 1.0 (phr)

Mercaptobenzothiazole Less than 1.0 (phr)

Wing stay L Less than 1.0 (phr)

Zinc oxide Less than 5.0 (phr)

Diphenylguanidine Less than 0.7 (phr)

Sodium silicofluoride 0.5 - 1.0 (phr)

The oil-based absorbent foam from the process as according to claim 1. in which the density was 0.28-0.56 g/cm³.

The oil-based absorbent foam from the process as according to claim 1. in which the characteristic was open pore diameter less than 100 micron.