Adhesive Manufacture

The main uses of resorcinol are in the manufacture of mbber and wood adhesives. Manufacturing capacity is about 30,000 t/yr worldwide. World average prices in November 1993 are reported for the main derivatives in Table 2. 

In the case of low temperature tar, the aqueous Hquor that accompanies the cmde tar contains between 1 and 1.5% by weight of soluble tar acids, eg, phenol, cresols, and dihydroxybenzenes. Both for the sake of economics and effluent purification, it is necessary to recover these, usually by the Lurgi Phenosolvan process based on the selective extraction of the tar acids with butyl or isobutyl acetate. The recovered phenols are separated by fractional distillation into monohydroxybenzenes, mainly phenol and cresols, and dihydroxybenzenes, mainly (9-dihydroxybenzene (catechol), methyl (9-dihydtoxybenzene, (methyl catechol), and y -dihydroxybenzene (resorcinol). The monohydric phenol fraction is added to the cmde tar acids extracted from the tar for further refining, whereas the dihydric phenol fraction is incorporated in wood-preservation creosote or sold to adhesive manufacturers. Naphthalene Oils. Naphthalene is the principal component of coke-oven tats and the only component that can be concentrated to a reasonably high content on primary distillation. Naphthalene oils from coke-oven tars distilled in a modem pipe stiU generally contain 60—65% of naphthalene. They are further upgraded by a number of methods. 

There are some aspects in the raw dry NR grades for adhesive manufacturing to be considered. NR tends to suffer oxidative degradation catalyzed by metals (mainly copper). The susceptibility of NR to oxidation can be measured using the plasticity retention index. The better grades of rubber have the higher plasticity retention index. 

Forms of SBR. SBR is sold for adhesive manufacturing as latices or in solid form. 

The degree of agglomeration of fillers affects the dispersion and the rheological properties of adhesives [41], and disagglomeration of fillers during adhesives manufacturing should be produced to obtain acceptable properties. 

Adhesion depends on a number of factors. Good adhesion is defined by most customers as substrate failure. The major adhesive manufacturers possess equipment that allows them to make bonds with customer substrates under conditions that closely simulate actual packaging lines. These bonds are peeled either automatically or by hand to gauge adhesion. The most important factors influencing adhesion are the wet-out of the substrate, partieularly by the polymer component of the adhesive system, and the specific adhesion with the substrate. Choice of resin is critical for both. Rosin, rosin esters and terpene phenolics are eommonly added for these purposes in EVA and EnBA-based systems. Adhesion at low temperatures is also influenced by the overall toughness of the system at the test temperature. 

Adhesives - Methyl chloroform has been used extensively by the adhesives manufacturing industry because of its characteristics - it is nonflammable and quick drying, and it does not contribute to local air pollution. One alternative for some applications is water-based adhesives. 

Gliwice, Institute for Plastics Processing, 2004, Paper 46, pp.9, 29 cm, ISBN 839176933X 012 COATINGS, INKS AND ADHESIVE MANUFACTURE DEMONSTRATING COMPLIANCE WITH THE SOLVENT EMISSIONS DIRECTIVE Newbould T... 

The Solvent Emissions Directive was adopted in March 1999 by the European Council of Ministers and should be implemented by member states within two years. The adhesives industry uses about 130,000 tonnes of solvents in its products annually and has a key role to play in meeting the Directive s targets. The main impact of emissions reduction will be on adhesives coaters because the adhesive film forms through the evaporation of solvent. For adhesives manufacturers, the main issue is the reduction of fugitive emissions. Both oxidation and recovery are well proven abatement techniques. BELGIUM EUROPEAN COMMUNITY EUROPEAN UNION WESTERN EUROPE... 

An examination is made of a European Union directive aimed at limiting emissions of volatile organic compounds arising from the industrial use of organic solvents. Proposed emission limits applicable to the use of solvents in coatings, inks and adhesives manufacture, adhesive bonding and rubber processing are presented. 

Labels (made of paper or plastic) are usually applied to the filled package by a labelling machine. If the package has been filled below the dew point, then the package is likely to be wet by the time the label is applied. Special adhesives are therefore used and suitable advice can be provided by adhesive manufacturers. 

Sterile reusable devices have undergone significant market growth over the past several years due to advances in less invasive surgery. To the adhesive manufacturers, resposables may be considered to have the same requirements as sterile reusables. 

These guidelines were originally developed for testing the suitability of plastics used in medical devices that may come into contact with bodily fluids, but they have been extended to adhesives as well. Generally, products are tested by an independent laboratory. The results are typically provided to device or adhesive manufacturers in the form of certifications of compliance on an as-requested basis. Meeting these standards verifies that the successfully tested products are nontoxic and biologically inert in the cured state. 

Epoxy adhesives have achieved their commercial success due in no small way to their processing capabilities. Epoxy chemistry is compatible with (1) a variety of formulating techniques and processes accessible to the adhesive manufacturer and (2) a variety of application and curing methods accessible to the end user. 

Most of the raw materials used in large quantities in structural adhesives are used because they are widely available, relatively safe, and inexpensive. Quite often they are made in large quantities for uses other than adhesives and the adhesive manufacturers have taken advantage of supply and price. Few new basic raw materials are being developed specifically for the adhesive industry although the traditional raw materials are being combined in new ways to enhance desired adhesive properties. New initiators, adhesion promoters, primers, and specialty chemicals are being developed for use in small quantities to provide wider application latitude and improved performance. 

U.S. Employment in Paints, Coatings Adhesives Manufacturing 57.6 Thous. 2009 BLS... 

Due to the economic incentives for conversion of skim milk to powdered lowfat milk in the United States and Canada, nearly all of the casein used by U.S.-adhesives manufacturers comes from overseas. Casein has, at various times, been imported from 20 different countries. Australia, New Zealand, Uruguay, France, Norway, Holland, Ireland, and Argentina are probably the most important producers in the Western World today. The worldwide nature of casein production leads to a wide range in product quality. 

One of the most important features of SBC adhesives is their versatility. Because they are thermoplastic materials of carefully controlled molecular weight, they can be applied both as hot melts and from solvent. More importantly, adhesive manufacturers can tailor their properties to match a wide range of applications. The primary competitors for SBCs in the pressure-sensitive adhesive market are acrylic copolymers. While acrylics have better specific adhesion to polar materials, adhesive manufacturers cannot easily formulate them for varied adhesion applications. 

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