INTRODUCTION

The rapid economic growth in Malaysia has generated 0.5-0.8 kg waste material/person/day and in rural areas the figure increased to 1.7 kg/person/day (Kathirvale et al., 2003). The authors noted that plastics materials constitute the largest component of waste material by weight at 18.9%, apart from food and paper. The plastics waste materials comprised 3.2% rigid plastics, 14% plastics film and 1.65% foam plastics. Most plastics such as poly-olefins, a petroleum derivative, are not easily degradable. This means that the plastics materials cannot be decomposed by bacteria when buried or disposed at the dumping sites. Pocket Guide to Marine Debris (2003) predicted that plastic bottles would take approximately 450 years to decompose.

Biodegradable plastics materials such as polyactic acid and polyhydroxybutyrate however, are too expensive to compete with petroleum based plastics. The government has faced difficulties in finding suitable dumping sites as well as outcry from the public whenever issues on the development of new dumping sites were raised (Jamlus, 2004).

The British Plastics Federation (2003) categorized recycled plastics as industrial scrap and post-use products. The former is derived from manufacturing scrap while the latter is plastic products that have undergone a full service life and later reclaimed for further use.

Plastics waste materials that are collected from industry sources that comes under the sorted plastics categories were claimed to be better in terms of quality than those collected from mixed material sources. It is relatively easier to identify and control the cleanliness of materials that are collected from the industry as compared to those from municipal waste. Better grade recyclable plastics will ensure better quality for the second grade plastics materials to be produced without the need for sorting and cleaning processes. Sorted plastics materials can be obtained from the industry or consumers that sort their own plastics waste materials.

The objective of this study is to determine the consumption and disposal rate of plastic materials in plastic manufacturing companies and to identify recycling trends in these companies as well as in recycling companies in Malaysia. Results from the study would provide some insights into issues related to the recycling pattern, supply and quality of recycled materials in Malaysia.

MATERIALS AND METHODS

The study was conducted in Malaysia from February-April 2005 using the survey method that was sent out to forty plastic manufacturing companies and detailed case studies involving interviews in three plastics recycling companies. The survey method was aimed at acquiring information related to the consumption of plastics and recycled materials, plastics recycling practices and issues in the plastics manufacturing companies while the detailed case studies were used to gather details on recycling practices in recycling companies. Respondents for the study were identified from the directory of companies registered with the Malaysian Plastics Manufacturers Association (MPMA Directory 2001/2002). Twenty plastics manufacturers responded to the survey. Findings from the survey and detailed case studies are reported in the following section.

RESULTS AND DISCUSSION

Recycling of plastics in plastics manufacturing companies
Consumption rate of plastics according to resin types: With regard to the type of resins consumed by the plastics manufacturers, results from the survey (Fig. 1) indicated that ABS-28%, PP-27%, PS-20%, other materials such nylon and acrylic 11%, PE-10% and PC-4% were the main resins used. The results clearly indicated that polyolefin such as polyethylene (10%) and polypropylene (27%) monopolised the plastics industry in Malaysia. This finding is in line with the study by the Malaysian Plastics Manufacturers Association (MPMA) that reports the consumption of poly olefins as the highest, at 67.7%.

The consumption of the ABS resin is high (28%) since most of the respondents are from the electrical and electronics sector; producing telephones, computer casings and domestic appliances such as casings for food processors and hand-held electrical items. PS is third in terms of consumption and this finding conforms to the study conducted by MPMA (2004).

Table 1:	Consumption rate for different types of plastics resin per day of the respondent companies

Fig. 1:	Consumption rate of plastics according to resin types

In terms of unit weight, the total amount of solid resins consumed per day by the respondent companies is

46.8 ton day^-1. The total consumption of polyolefin resins can be as high as 17.4 ton day^-1, which includes the use of recycled resins. Table 1 shows the amount of resins consumed per day by the respondent companies according to resin types.

Consumers of plastics according to industrial sectors: With regard to the consumption of materials according to industrial sectors (Fig. 2) the electrical and electronics sectors lead at 39%, followed by automotive 26%, domestic 19%, packaging 10%, building and construction and agricultural sectors, each contributing 3%. MPMA has

identified the packaging sector as the largest consumer of plastics material. The packaging sector manufactures product using the extrusion method such as film extrusion to produce plastic bags and blow moulding to produce bottles etc. A majority of the respondents in this study use the injection moulding process for their products.

The injection moulding process uses less material as compared to the extrusion method since the extrusion method is a continuous process (Abidin, 2005). In the UK, packaging represents the largest single sector in plastics use; that accounts for 35% of UK plastics consumption (Waste online, 2006).

Consumption of virgin resin versus recycled resin: All the respondents use thermoplastic materials, enabling them to reprocess or recycle the materials. Injection moulding is the main process in most of the respondents.

Fig. 2:	Consumption (in %) of plastics according to industrial sectors

From the total of 46.8 ton day^-1 plastics materials consumed by the respondents, 19% are of the second grade material or recycled materials that have been mixed with virgin resin. The other 81% used virgin resin. Some manufacturers mixed less than 10% of the recycled materials into the virgin resin. According to the British Plastics Federation (2003) almost all moulding companies recycle their own plastic waste in-house. From the survey, it was found that 7 companies emphasised quality in their end products while saving on cost. 3 out of the 7 companies do not use recycled materials at all due to the need to produce high precision products as specified by the customer. Some companies use more than 50% of mixed recycled material in most cases for the manufacture of domestic products that do not require high quality or accuracy.

According to MPMA (2004) the total consumption of virgin plastics increases from 1.42 million metric tonne in 2003 to 1.53 million metric tonne in 2004. About 40% of the virgin plastic is imported due to the absence of the required grade and type in the local market.

Sources of plastics materials in the industry: Out of the 20 respondents, 80% used recycled materials. Many companies recycled their own materials in view of cost savings. Twenty percent of the companies that used recycled materials recycle their products in-house as well getting the supply from external recycling companies that are appointed on a contract basis. The recycled products are generally defects or those that do not comply with the specified quality standards. The British Plastics Federation (2003) refers to these scrap materials as industrial scrap that results from the start up and shut down periods of the processing machinery, from out of specification products and from quality control samples.

Outsourcing of the recycled materials is necessary when its capacity to support production requirements is low.

Fig. 3:	Sources of plastics materials for the plastics manufacturers

Ten percent of the companies that use recycled material do not recycle their waste materials, instead they outsourced from recycling companies. None of the recycled materials are imported perhaps due to the availability of supply from the local recycling companies.

It has been noted that in developing countries, the scope for plastics recycling is growing as the amount of plastics being consumed increases (Recycling of Plastics, 2006). Figure 3 depicts the various sources of plastics materials. The other 20% of the respondents who did not use recycled materials did so due to requirements for high quality products. Waste materials from these companies are sold as scrap through quotations or to contractual buyers.

Consumption of recycled plastics according to industry size: In Malaysia, the industry is classified according to sizes based on the following category: small sized- full time employee less than 50, annual sales less than RM10 million; medium size-full time employee 50-150 and annual sales between RM10 million-RM25 million; large size- employee more than 150 and annual sales more than RM25 million. Findings from the study indicated that the medium-sized industry consumed the most recycled material, at 4 ton day^-1 (43%) compared to the large industry at 2.9 tonne/day (40%) and small industry at 1.9 ton day^-1 (17%).

Rate of disposal of plastics materials: Findings from the study indicated that plastics materials are disposed at a rate of 2.943 kg day^-1, an approximation of 5% from the daily consumption of plastics material. This finding is in agreement with the results obtained by Rossbach (1979) at 5.3%.

Recycling of plastics materials in plastics recycling companies: The findings discussed in this section were obtained from detailed case studies conducted in three plastics recycling companies (industrial partners). These companies are Bumiputera-owned companies that are categorized as small scale industries (full time employees <50 and annual sales <RM10 million).

Recycling process: The main processes involved in recycling in the industrial partners are presented as follows:

Not all materials that are obtained from the industry will undergo the pelletising process especially materials from the injection moulding process (Abidin, 2005).

Materials that are purchased directly from local producers of resin will be cleansed, packaged and eventually marketed. Generally, materials that are obtained from the local suppliers do not require classification since the material specification can be obtained directly from the suppliers. The process flow for plastic recycling in the industrial partners is presented in Fig. 4.

Sources of recycled plastics: From the case studies, it was observed that recycled materials might be obtained from several sources as outlined in the following:

Material grade and quality: The price of the recycled material is generally classified according to the grade and quality of the recycled materials as follows:

Fig. 4:	Process flow for plastic recycling in the industrial partners

CONCLUSIONS

In Malaysia, one of the prime movers for the expansion of the plastics industry is the plastic recycling companies. Findings from the study indicated that 19% of the plastics materials used are recycled materials and their supplies are either from in-house or local recycling companies. This study found that 20% of the manufacturing companies recycled their own materials as well as hiring external recycling companies to mesh their products into flake-forms. The material flow pattern within the plastics manufacturing company enables the re-use of materials of the same grade. Ten percent of the manufacturing companies purchased second grade materials in the form of pellets or flakes. Three possible reasons were cited i) the lack of facilities for recycling, ii) high demand for recycled materials causing manufacturers to be incapable of recycling their own material, or iii) the need to develop products of a higher quality by using second grade materials that has been pelletized; pellets are deemed better than meshed materials.