Rubber Product Manufacturing Industry

RUBBER PRODUCT MANUFACTURING

INDUSTRY

Kristine Reyes1/21/2010

Kristine M. Reyes 1995-55585 1

NATURE OF THE RUBBER PRODUCT MANUFACTURING INDUSTRY

The first manufacturers of rubber products were said to be the Amazon people. It was

only in the nineteenth century that Europeans started using rubber to create waterproof clothing

and equipment. Rubber product manufacturing was relatively small scale then and it was not

until 1839 when Charles Goodyear developed vulcanization that this industry grew.

Vulcanization is actually the technique utilized by rubber product manufacturers which modifies

the chemical structure of rubber making it strong enough to resist extreme heat and cold (Rubber

Product Manufacturers, 2005). At the turn of the twentieth century, “rubber boom” took place

resulting to expansion of rubber plantations and rubber product manufacturing worldwide. The

invention of bicycles followed by automobiles which requires the use of tires promoted the

global demand for rubber. During the latter part of the twentieth century, increasing costs of

natural rubber, mostly produced in Southeast Asia, paved the way for rubber product

manufacturers to utilize synthetic rubber compounds. New types of synthetic rubber compounds

with specialized properties and applications were developed by rubber product manufacturers to

meet the demands of an increasingly technological world (Rubber Product Manufacturers, 2005).

Synthetic rubber is mainly produced in industrialized countries such as the United States, Japan,

countries in Western and Eastern Europe. Brazil is the only developing country with a

significant synthetic rubber industry (Belisizky & Fajen, 1998).

The rubber product manufacturing industry is made up of businesses involved in

processing natural, synthetic or reclaimed rubber materials to generate various intermediate or

final products. More than 40,000 different products can be made from rubber. In most

countries, the industry is divided into two sectors: tire and non-tire. The tire manufacturing

industry comprises establishments primarily engaged in manufacturing tires and inner tubes from

natural and synthetic rubber and in retreading or rebuilding tires (U.S. Census Bureau, 2007).

Tire and tire products account for 60% of synthetic rubber use and 75% of natural rubber

consumption (Belisizky & Fajen, 1998). The non-tire sector covers companies involved in the

manufacture of other rubber products from belts, hoses, to footwears, birth control devices and

gloves. Non-tire rubber products are used by virtually all industries but the dominant market is

the automotive sector. Rubber hoses, belts, airbags, mats, gaskets and bumpers are just some

products that are being manufactured for use in automobiles.


ECONOMIC RELEVANCE OF RUBBER PRODUCT MANUFACTURING INDUSTRY

The rubber industry has a tremendous global impact. Products made from rubber have

become vital to all kinds of human activities increasing their demand. In 2005, consumption of

natural rubber worldwide reached 8.74 million tons while utilization of synthetic rubber was

pegged at 11.92 million tons (Maspanger, Budiman, Syamsu, & Haris, 2006). The global

demand for industrial rubber products is estimated to rise to 4.3% annually through 2013 to

$97.8 billion (Rubber Industry Global Overview).

According to IBIS World U.S. Industry Report, the rubber product manufacturing

industry in the U.S. has total revenue of $15.3 billion in 2010 with a revenue growth of 3.2%. It

exported $770 million worth of merchandise to other countries. In 2004 the industry employed

173,000 workers in more than a thousand manufacturing plants. Approximately $2.8 billion was

generated by employees working in this industry in 2010.

A look at the rubber industry in the Philippines reveals that the country ranks sixth in

world rubber production with a total of 99.7 thousand hectares of rubber planting mainly in

Mindanao and Palawan (Maspanger, et. al., 2006). The domestic production of rubber has

grown substantially over the past seven years from 214,575 metric tons in 1999 to 315,600

metric tons for the year 2005 (Raymundo, 2007). The Bureau of Postharvest Research and

Extension (BPRE) reports that domestic consumption of rubber in 2006 was 160,000-180,000

with a 15-20% increase in demand annually. Seventy percent of the total natural rubber

production is utilized by the tire and construction industries while the rest goes to other non-tire

products. The rubber product manufacturing sector with about 160 companies employs almost

15,000 people, or an equivalent of more than 90 people employed per manufacturing

establishment. In 1996, the Philippines exported $61.5 million worth of rubber products. These

are exported mainly in Taiwan, mainland China, Malaysia, Singapore, Hong Kong and Germany.

PROCESSES IN RUBBER PRODUCT MANUFACTURING

There are seven basic processes in manufacturing rubber products: mixing, milling,

extruding, calendaring, building or fabrication, vulcanizing and finishing.

The first step in the rubber product manufacturing process is mixing which involves the

production of rubber mix from raw and/or synthetic rubber and the addition of various additives.


The additives depend on the desired composition of the product and usually include filler,

extender oils, accelerators and antioxidants. The process requires weighing and loading of these

ingredients in a mixer, known as “Banbury” mixer, in order to combine them. The mixer creates

a homogenous rubber mass which is then discharged to or placed in a rubber sheeting mill. This

equipment will form the rubber into long strips or sheets. During this process, the formed sheets

of rubber pass through water-based “anti-tack” solution to prevent them from sticking together.

Then the sheets are cooled using cool air or through contact with cooling water. After cooling,

the sheets or rubber are passed through another mill to warm them up for further processing on

extruders and calendars.

Extruders transform the rubber into various shapes by forcing it through dies. Calendars,

on the other hand, receive hot strips of rubber from mills and squeeze them into reinforcing fiber

or cloth-like fiber materials to form thin sheets of rubber coated materials. Non-reinforced,

thickness-controlled sheets of rubber can also be produced by calendars.

Next, extruded and calendered components are combined with wire, polyester and other

reinforcing materials to produce various rubber products. To enhance the bonding of the various

product layers, adhesives called cements may be used. This fabrication, reinforcing, pre-curing

and bonding process is referred to as building.

All rubber products undergo vulcanization or curing. During this process, the elastic

quality of the rubber is enhanced through cross-linking of the polymer chains in the rubber

matrix. There are three widely used methods of curing: press mould curing, autoclave curing,

and hot air curing. Press mould curing uses high temperature and pressure and is often used for

tire and engineered rubber products. Autoclave curing utilises saturated steam and high pressure

and is predominantly used in non-tire rubber manufacturing facilities. Hot air curing involves

the passing of uncured products through a chamber with a heated atmosphere. This process is

used to final cure preformed products. The last process is finishing which may include grinding,

printing, washing, wiping and buffing to remove rough edges and other blemishes from the final

product.


OCCUPATIONAL HEALTH AND SAFETY CONCERN

The process of manufacturing of rubber products entails health and safety hazards from

the raw materials and from the various equipment used. This section discusses the different

hazards present in these manufacturing plants.

A. Chemical hazard

The manufacture of rubber products subjects workers to exposure to various

chemicals. These chemicals are grouped into various functional categories: elastomers,

fillers, antidegradents, vulcanizing agents, solvents, accelerators, activators, retarders,

reinforcing agents, pigments and dyes, antitack agents, bonding agents and miscellaneous

chemicals (Sullivan, Van Ert, & Lewis, 2001). Exposure to these chemicals may be

through inhalation or skin absorption. Concern for cancer risk among rubber products

workers was raised even in the 1920’s and 1930’s. Various studies revealed excess

deaths from bladder, lymphatic and hematopoietic, lung, stomach and colon, prostate,

liver and biliary and esophageal cancers among these workers. The lymphatic and

hematopoietic cancers were associated with exposure to benzene (which was widely used

in rubber industry many years ago) and 1,3-butadiene.

Adverse respiratory effects are also reported in some studies conducted by

Harvard University. Increased prevalence of respiratory symptoms and chronic disabling

pulmonary diseases such as emphysema were noted among rubber workers in the curing,

processing (premixing, weighing, mixing, and heating of raw ingredients), and finishing

and inspection areas of tire and non-tire plants (National Institute for Occupational Safety

and Health, 1997).

Direct contact with rubber and the different chemicals used in this industry have

resulted to cases of adverse skin reactions such as irritant contact dermatitis, allergic

contact dermatitis, contact urticaria (hives), aggravation of pre-existing skin diseases and

other less common skin disorders such as oil folliculitis, xerosis (dry skin), miliaria (heat

rash) and depigmentation from certain phenol derivatives (Taylor & Leow, 1998). The

most common skin reaction is irritant contact dermatitis caused by exposure to strong

chemicals or weaker irritants found in wet work and frequent use of solvents. Allergic


contact dermatitis is due to contact with accelerators, vulcanizers, anti-oxidants and anti-

ozonants.

B. Physical hazard

Rubber products workers are also exposed to noise. Machines used in the

different process operations are the main source of noise in the work environment. Noise

exposure may be attributed to machine operation, generator operation, boiler operation,

mechanical workshop and cutting, grinding and finishing operations (Maspanger, et. al.,

2006).

Heat poses a concern for workers stationed in the curing or vulcanizing process.

Rubber products are shaped in their desired forms through application of high

temperature and pressure. Workers are at increased risk for burn injuries secondary to

contact with hot surfaces of curing machines. In hot air curing, workers are exposed to a

hot environment because this involves passing uncured products through a chamber with

a heated atmosphere.

C. Ergonomic hazard

Musculoskeletal disorders have been reported in rubber product manufacturing

plants particularly in tire industry. Risk factors that were identified include static,

awkward postures in the back, shoulders and wrists, rapid motions in the wrist and back,

and large weights handled, as well as large forces applied to the trunk while handling

large pieces of rubber during tire building (Marras, 1998). Back injuries are common

problems as well as wrist problems like carpal tunnel syndrome and tenosynovitis. In

tire-building operations, disorders of the lower back are attributed to the heavy loads

being handled. Performing this task during asymmetric motions of the trunk and for

longer duration aggravates the problem.

D. Safety hazard

Safety hazards are largely observed in the operation of milling and calendaring

machines. Running nip accidents (getting caught in the rotating rolls) are common

causes of injuries. Several issues are identified with the problem of mill safety: mill

height, the size of the operator, auxiliary equipment, the way the mill is worked, the tack


or stickiness of the stock and stopping distance. These concerns contribute to the overall

safety of the workers when it comes to the operation of the mills.

Sources of injuries in the operation of calenders include clearing jams and

adjusting material, running nip injuries, threading up and communications. The increased

speed in calenders and lack of sensing device likewise serve as factors for most of the

accidents associated with these machines.

PRIORITY HEALTH AND SAFETY PROGRAM

In the rubber product manufacturing industry the predominant hazards that are identified

are chemical agents. A comprehensive program covering issues regarding this hazard should be

implemented. First of all, a complete inventory of the chemicals used for each process should be

made with corresponding MSDS for each chemical made available and displayed. Proper

storage and labelling of containers for these chemicals should be observed to avoid accidental

spills or mix-ups. Workers directly in contact with them should undergo proper training on their

handling and use as well as training on the appropriate personal protective equipment to be

utilized. Engineering controls should also be placed or applied to eliminate or reduce exposure

such as isolation, local exhaust ventilation and automation. Measurements of concentration of

the chemicals in the work environment (if available) can also be done periodically to monitor if

TLVs are still being met.

Noise exposure should also be addressed in this industry. Audiometry should be included

in pre-employment and annual physical examinations. Engineering control measures involve:

structural and mechanical modifications; proper maintenance of the machines; provision of

silencers on compressed air exhausts; replacement of old gear drive motors with new belt drive

ones; plugging of air leaks; reducing the transmission path of noise from the source to the

receiver; and providing proper acoustic enclosures, vibration insulator paddings for the noise-

generating machines and generators (Maspanger, et. al., 2006). Regulating the length of noise

exposures by proper shift scheduling or job rotation can also be adopted by the management.

The workers should be educated on possible consequences of excessive exposure and the

importance of the use of PPEs and their correct usage and maintenance.


Safety hazards can be minimized by ensuring that workers understand and observe proper

procedures when operating the machines. New machine operators must undergo training before

going on board and regular retraining thereafter. Safety signage must be in place as reminders

for workers to reduce work-related accidents or injuries. Vital to the program on safety hazards

is the implementation of engineering controls. The following can be adopted when appropriate:

use of electrical switch off systems and mechanical breaks to stop blade rotation when workers

are in close proximity to the revolving parts; installation of emergency stop switches within

reach of operating stations; use of guards to prevent access to material feed openings and

discharge points; use of screens or flaps to protect against material flying out; and use of lock

out-tag out procedures. Regular maintenance of the equipment and machines should also be

observed.


REFERENCES

Rubber Product Manufacturers. (2005). Retrieved January 18, 2011, from Meere Industries: http://www.meererubbermolding.com/rubber-product-manufacturers.htm

Rubber Product Manufacturing. (2010). Retrieved January 20, 2011, from IBIS World: http://www.ibisworld.com/industry/default.aspx?indid=529

Belisizky, L. S., & Fajen, J. (1998). Rubber Industry General Profile. In J. Stellman (Ed.), Encyclopedia of Occupational Health and Safety (4th ed.). Geneva: International Labor Office.

Bureau of Postharvest Research and Extension. (2007). Philippine Postharvest Industry Profile: Rubber. Retrieved January 18, 2011, from http://www.philmech.gov.ph/phindustry/rubber.htm

International Finance Corporation. (2007). Environmental, Health and Safety Guidelines for Metal, Plastic and Rubber Product Manufacturing. Retrieved from International Finance Corporation: http://www.ifc.org/ifcext/enviro.nsf/AttachmentsByTitle/gui_EHSGuidelines2007_MetalPlasticRubber/$FILE/Final+-+Metal,+Plastic,+and+Rubber+Products+Mnfg.pdf

Marras, W. S. (1998). Rubber Industry Ergonomics. In J. Stellman (Ed.), Encyclopedia of Occupational Health and Safety (4th ed.). Geneva: International Labor Office.

Maspanger, D., Budiman, A., Syamsu, Y., & Haris, U. (2006). Priority Integration Sector Specialist–Rubber Based Products. ASEAN Secretariat.

National Institute for Occupational Safety and Health. (1997). Special NIOSH Hazard Review:Rubber Products Manufacturing Industry. Retrieved January 18, 2011, from Centers for Disease Control and Prevention: http://www.cdc.gov/niosh/rubberhr.html

National Pollutant Inventory. (2001). Emission Estimation Technique Manual for Rubber Product Manufacture. Australia.

Raymundo, R. B. (2007). Determining the Role of the Philippine Natural Rubber and Rubber Based Products Manufacturing Industries in the ASEAN Economic Integration Plan. Manila.

Rubber Industry Global Overview. (n.d.). Retrieved January 18, 2011, from Industrial Rubber Goods: http://www.industrialrubbergoods.com/global-overview.html


Rubber Industry Job Descriptions, Careers in the Rubber Industry, Salary, Employment. (n.d.). Retrieved January 18, 2011, from http://careers.stateuniversity.com/pages/604/Rubber-Industry.html

Sullivan, J. B., Van Ert, M. D., & Lewis, R. (2001). Tire and Rubber Manufacturing Industry. In J. B. Sullivan, & G. R. Krieger (Eds.), Clinical Environmental Health and Toxic Exposures. Philadelphia: Lippincott Williams & Wilkins.

Taylor, J., & Leow, Y. H. (1998). Rubber Contact Dermatitis and Latex Allergy. In J. Stellman (Ed.), Encyclopedia of Occupational Health and Safety (4th ed.). Geneva: International Labor Office.

Townhill, J. R. (1998). Rubber Industry Safety. In J. Stellman (Ed.), Encyclopedia of Occupational Health and Safety (4th ed.). Geneva: International Labor Office.

U.S. Census Bureau. (2007). Plastics and Rubber Products Manufacturing. Retrieved January 18, 2011, from U.S. Census Bureau: http://www.census.gov/naics/2007/def/NDEF326.HTM

“This is an original work submitted by the undersigned in fulfilment of the requirements of OH

206. References are cited accordingly.”

Kristine M. Reyes

1995-55585

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Rubber Product Manufacturing Industry