How can elevated temperature shear properties of a natural-rubber based pressure-sensitive adhesive be improved?

The use of higher softening point resins has been shown to greatly improve the shear adhesion failure temperature (SAFT) as well as both room temperature and 50°C holding power of natural rubber based pressure sensitive adhesives (PSAs), although some tack properties such as rolling ball tack may decrease when using higher melting point tackifying resins. The exact improvement will depend on the specific formulation and testing conditions, but as much as 10°C improved SAFT and 5 times the room temperature and 50°C shear was found to result in lab work using a 1.2/1 ratio of tackifier to natural rubber polymer with 10% plasticizing oil when Eastotac™ H-130E was substituted for Eastotac™ H-100E resin.

Will CP 310W Water-Reducible Chlorinated Polyolefin Adhesion Promoter, CP 347W Water-Reducible Chlorinated Polyolefin Adhesion Promoter, or Eastman™ CP 349W Water-Reducible Chlorinated Polyolefin Adhesion Promoter give properties equivalent to solventborne adhesion promoters?

Waterborne CPOs are generally just as effective as solventborne CPOs if used in an application where cure temperatures are 250°F (121°C) or higher for 30 minutes. At lower temperatures, formulation variables of waterborne systems that contain waterborne CPOs have a major effect on adhesion performance. The type and amount of surfactant and neutralizer added or introduced with other components can affect performance. The same is true of the polymer properties such as Tg and acid number of other polymers present. Cosolvents can also have an effect on adhesion performance.

What publications are available on the application of Eastman™ adhesion promoters?

Eastman Publication GN-424 titled “Solventborne Adhesion Promoters For Untreated Polyolefin Plastics” and Eastman Publication GN-408 titled “How To Use Eastman™ CPOs As Adhesion Promoters” are available.

Does Eastman offer any non-chlorinated adhesion promoters?

Yes, Eastman™ AP 550-1. Eastman™ AP 550-1 provides excellent adhesion when used under 1K/2K, 2K/2K, and 1K/1K basecoat/clearcoat paint systems. In addition, Eastman™ AP 550-1 exhibits excellent gasoline resistance when topcoated with a variety of paint systems. Eastman™ AP 550-1 can also be blended with other chlorinated polyolefin adhesion promoters, such as CP 730-1, to optimize overall adhesion promoter performance properties.

Can waterborne Eastman™ CPOs be used as stir-in additives?

Yes, but this will be system dependent. One should determine the compatibility and stability of the waterborne CPO with the coating system or resin of interest before use.

Which products does Eastman offer in low-HAPs solvents?

Eastman™ Chlorinated Polyolefin 343-1 and Eastman™ Chlorinated Polyolefin 343-3 are supplied as 25% solids in Aromatic 100. Eastman™ Chlorinated Polyolefin 515-2 is available as 40% solids in Aromatic 100 solvent. Eastman™ Chlorinated Polyolefin 730-1 (targeted commercialization mid-2002) is supplied at 25% in Aromatic 100 solvent.

What is the major difference between Eastman™ chlorinated polyolefin 343-3 and Eastman™ chlorinated polyolefin 515-2?

Eastman™ chlorinated polyolefin 343-3 and Eastman™ chlorinated polyolefin 515-2 are made from different base polymers, but both have approximately 30 wt.% chlorine levels that make them more soluble and more compatible with other coating resins and solvents. Eastman™ chlorinated polyolefin 343-3 and Eastman™ chlorinated polyolefin 515-2 are used in coatings, inks and adhesives applications.

Which Eastman™ adhesion promoter is recommended for use as an adhesion promoter for polyethylene?

Eastman™ Chlorinated Polyolefin 153-2.

Which solvent borne adhesion promoters are recommended for use as primers for polypropylene and thermoplastic olefin (TPO)?

Eastman™ chlorinated polyolefin (CPO) adhesion promoters CP 730-1, CP 164-1, and CP 343-1. Eastman's non-chlorinated adhesion promoter, AP 550-1, is also used in primer applications. These adhesion promoters are supplied in a variety of solvents and concentration forms.

To obtain adhesion for one-step coatings for polyolefin plastics, can the adhesion promoter be simply postadded to the existing coating formula?

Postaddition may be possible, but the compatibility of the adhesion promoter with the coating system should be checked prior to use. Ideally, the adhesion promoter should be formulated into the coating at an optimum level and stability testing (under hot and cold conditions) of the coating system should be checked prior to use. Levels of addition may depend on coating and substrate type.

Is there an alternative to chlorinated polyolefin adhesion promoters?

Eastman has developed a nonchlorinated adhesion promoter for PP and TPO, Eastman™ AP 550-1 (25% in xylene). Eastman™ AP 550-1 provides excellent adhesion when used under 1K/2K, 2K/2K, and 1K/1K basecoat/clearcoat paint systems. In addition, Eastman™ AP 550-1 exhibits excellent gasoline resistance when topcoated with a variety of paint systems.

What is a TPO and what factors affect adhesion to TPOs?

TPO is a general abbreviation for thermoplastic polyolefin. Thermoplastic polyolefin generally describes that family of plastics made of polypropylene modified with an impact modifier. Common impact modifiers used are ethylene-propylene diene monomer (EPDM), plastomers, and low molecular weight polyolefin. The level of impact modifier may be as high as 40% in some TPOs that use EPDM or as low as 5%–8% using the other impact modifiers. The flexural modulus (stiffness) of TPOs varies widely and as a general rule obtaining paint adhesion to those with higher flexural modulus is more difficult.

This answer/suggestion/or other is based on intuitive interpretation of related data and experience and as such has no direct substantive supporting data. You should therefore be guided in your evaluation of the sufficiency of this answer by making your own independent evaluation as to what will or not work for solving the problem facing you.

What is a common adhesion promoter for automotive plastics?

CPOs or other modified polyolefins are often used in adhesion promoter primers or as additives to coatings that are applied to polypropylene (PP) and thermoplastic olefin (TPO).

Is there a universal adhesion promoter that is good for a variety of plastics such as polyethylene, polypropylene, thermoplastic polyolefin, ABS, nylon, PVC, and other plastic polymers?

There is no universal adhesion promoter that is good for all coatings and all surfaces. Each of these materials presents unique challenges for obtaining adhesion of a variety of coatings.

Why are coatings difficult to adhere to plastics?

Plastic substrates have low surface energy compared to other materials and are thus difficult to wet. Plastic substrates are also nonporous and resistant to most solvents. The plastic surface gives coatings little opportunity to penetrate the surface or physically lock into surface irregularities that would improve adhesion.

What is an adhesion promoter?

An adhesion promoter is used as an additive or as a primer to promote adhesion of coatings, inks, or adhesives to the substrate of interest. An adhesion promoter usually has an affinity for the substrate and the applied coating, ink, or adhesive. Without the adhesion promoter, the properties of the applied coating may not be sufficient to meet the performance requirements needed for the end product such as a painted automotive plastic surface. In automotive coatings, the term adhesion promoter refers to the primer, which achieves adhesion of the subsequent paint layer to TPO substrate. This adhesion promoter is usually comprised of chlorinated polyolefin (CPO) as the active adhesion-promoting component, other resins, and pigment.

Which Eastman™ solvents are available in Urethane Grade?

A solvent is defined as urethane grade when the water content does not exceed 0.05%, maximum.

The following Eastman™ solvents are available as urethane grade:

  • Eastman™ n-Butyl Acetate
  • Eastman™ Isobutyl Acetate
  • Eastman™ n-Butyl Propionate
  • Eastman™ Isopropyl Acetate
  • Eastman™ DE Acetate
  • Eastman™ MAK
  • Eastman™ EB Acetate
  • Eastman™ Methyl Acetate – High Purity
  • Eastman™ EEP Solvent
  • Eastman™ MIAK
  • Eastman™ Ethyl Acetate (99%)
  • Eastman™ MPK
  • Eastman™ 2-Ethylhexyl Acetate
  • Eastman™ PM Acetate
  • Eastman™ IBIB
  • Eastman™ n-Propyl Acetate

Does Eastman offer any solvents that have been exempted as VOCs?

In 1995, the EPA deemed acetone to be VOC exempt and in 1998, methyl acetate was also ruled VOC exempt. Formulators can now use as much acetone or methyl acetate as desired without reporting them as VOCs. Acetone and methyl acetate are considered fast evaporating solvents.

After applying my coating, the resin appears to have a solvent blush during drying. What could be the source of this problem?

Remember the formulator’s “rule of thumb” that the last solvent to evaporate from the coated substrate must be active for the resin. This solvent must readily dissolve the resin used in the coating system and is often referred to as the “tail” solvent or “retarder” solvent. If the solvent is not active for the resin, the resin will kick out of solution leading to many film integrity problems. The evaporation rate of tail solvents is usually low. The EASTMAN Chemicals Wizard website has information about evaporation rates, resin solubility and other properties. The EASTMAN e-Solvents Chart® program provides pertinent technical and regulatory information for Eastman and non-Eastman solvents and their compatibility with specific resins. Listed below is a link to that website: https://ws.eastman.com/Wizards/eSolvents/ESolvDefault.asp.

What is a premium retarder solvent for replacing ethyl glycol ether?

To meet the challenges of the coating industry, Eastman™ EEP, a linear ether-ester solvent, was developed. In terms of solvent activity and evaporation rate, the performance of Eastman™ EEP solvent is very similar to ethyl glycol acetate (EGA). This product is not an ethylene oxide derivative and is not on the HAPs list. Compared with other retarder solvents of similar evaporation rate, EEP often provides lower resin solution viscosity, which in turn allows higher solids content at application viscosity. Suggested uses for this solvent include industrial lacquers and enamels, maintenance enamels, primer surfacers, polymer synthesis media, high solids coatings, and thinners.

How can humidity blush be stopped?

Humidity blush is the formation of a haze or opaque appearance when moisture condenses on the film surface. A humidity blush coating maintains its integrity as a coating. This type of blush can be stopped by using a slower (evaporation rate) solvent with high blush resistance such as Eastman™ IBIB (isobutyl isobutyrate). For additional information see this online publication: M-270.

What is a photoresist ink and how is it used in the semiconductor industry?

Photoresist inks are formulated with photosensitive polymers that are coated onto a silicon wafer. Typical positive photoresist ink would contain the following ingredients:

Positive Photoresist 1

  • Diazonaphthoquinone (photoactive compound)
  • Novolac resin
  • Stabilizer
  • Polymerization inhibitors
  • Viscosity control agent
  • Dyes
  • Plasticizers
  • Solvents (Eastman EastaPure MAK, Eastman EastaPure PM Acetate, Eastman EastaPure n-Butyl Acetate, and EASTMAN EEP solvents have been used in photoresist ink formulations).

1 Information from SRI International "Electronic Chemicals" 1992

The photoresist inks after being coated onto the silicone wafer is dried and exposed to ultra violet light by a process called photolithography. This process allows pattern pathways to be developed for the microelectronic integrated circuits. Eastman provides high purity solvents called Eastman EastaPure&trade Electronic Chemicals for producing uniform coatings on the silicone wafers.

What is an edge bead remover?

During the spin coating of photoresist inks onto silicone wafers, the procedure makes a ridge or bead at the outer edges of the wafer. This must be removed with high purity solvents to give uniform thickness of coating across the wafer. The uniform coating allows for proper focus of light onto the coated wafer during the photolithography process to design the microelectronic circuits. Eastman EastaPure™ Electronic Chemicals are used to remove edge beads.

What is wet chemical etching?

Silicone and metals can be removed in a controlled etching process using high-purity inorganic acids. Inorganic acids such as nitric, hydrofluoric, hydrochloric, phosphoric, and sulfuric are commonly used for etching. A mixture of acids called mixed acid etchants (MAE) is used for controlled etching containing nitric, hydrofluoric and acetic acid. Eastman EastaPure™ acetic acid is used with the inorganic acid in this mixture.

How much frothing agent is needed to use in a frothing cell?

The amount of frothing agent needed will vary according to the type and size of the ore and with the type of equipment. Typical amounts of the frothing agent are 0.01-0.50 pounds per short ton of ore or 0.005-0.25 kilograms per metric ton of ore.

What is the difference between Eastman™ 168 and Eastman™ 168-CA?

Both products are bis(2-ethylhexyl)-1,4 benzenedicarboxylate and are very good alternatives to orthophthalate plasticizers. Eastman™ 168-CA also contains an antioxidant that is 1,1,3-tris (2-methyl-4-hydroxy-5-t-butyl phenyl) butane. This antioxidant enables use in 60° wire. As the temperature of the wire increases, the plasticizers will become more likely to volatilize, thus changing the physical properties of the PVC over time. Underwriters Laboratories (UL) has developed a protocol (UL-83) to determine the change in physical properties as the vinyl samples are aged under elevated temperature. Under this protocol, the vinyl must retain 65% of the elongation properties after heat aging that were present before the aging process. Eastman™ 168-CA offers good permanence, good electrical properties, and superior low-temperature flexibility.

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