HQ 083986: Classification of Silane Coupling Agents

Native CBP ruling rendition. Applicability is fact-specific; modification/revocation relationships and original publisher date are retained. Publisher sentinel year0001 means unknown date, not a historical legal adoption.

 	HQ 083986

	April 7 1989

  
CLA2 CO:R:C:G  083986 JGH  835339

  CATEGORY:  Classification

  TARIFF NO.:  2931.00.5010

  Stephen S. Spraitzer, Esq.
  George R. Tuttle
  Three Embarcadero Center, Suite 1100
  San Francisco, California  9411

  RE: Classification of Silane Coupling Agents

  Dear Mr. Spraitzer:

       	This is in reference to your request for a classification  ruling under the Harmonized Tariff Schedule of the United  States (HTSUS) for two silane coupling agents, products of
  Japan.

  FACTS:



       	KBE 903 /(3triethoxysilyl) 1propanamine/ and KMB 403  [trimethoxy(3oxiranylmethoxy] propyl silane/ are described as  silane coupling agents to be used, among other things, for the  performance improvement of fiberreinforced plastics by direct
admixture to synthetic resins, improvement in paints and other coating materials and adhesives.

  ISSUE:

       	Whether the silane coupling agents are classifable under   the provision for other adhesives, not elsewhere specified or   included, adhesives based on rubber or plastics, in subheading   3506.91.00, HTSUS, or the provision for organoinorganic  compounds in subheading 2931.00.50, HTSUS.
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  LAW AND ANALYSIS:

       	You state that the purpose of these products is to enhance  the chemical bonding between an organic material and an  inorganic substance, and that their chief use is to increase
the adhesion of glass fiber products to plastic resins.  You  assert that the products belong to a class of organo silane  compounds having two or more reactive groups.  One of the groups reacts with inorganic materials to form a chemical bond with the surface material, while to other group is said to react with organic material to from a second chemical bond.

       	In the technical literature submitted it is noted that the  addition of a silane coupling agent is effective in improving  the mechanical properties of thermoplastic resins impregnated
 with an inorganic filler.  It is also stated that adhesive  bonding is improved between the organic synthetic resin and an  inorganic substrate  material when a silane couping agent is
used.

       	In application the silane coupling agents are said to be  applied in a 1 percent aqueous solution to 14 ply glass cloth,  air dried, and then heat treated.  Epoxy resin plate, an epoxy
 resin which is a liquid in its uncured state, is laminated  with a curing agent to the glass cloth, through the application  of heat and pressure.  In this process the coupling agents do not make the bodies adhere but assist in the bonding of the glass to the liquid matrix resins.  The resin subsequently  hardens to form objects such as fiberreinforced plastics  or  composite materials.

       	It should be noted that the products could be made without   the organofunctional silanes.  The silanes are not the primary  bonding agents but act as crosslinking or coupling agents,
  and when used in low concentrations, become part of the plastic  material system, that, on curing, bonds the glass cloth   together.

       	For tariff purposes, it is well settled that a product  which actually bonds two surfaces together is a cement, rather  than products which merely improve a cement's bonding
capabilities.  United States v.  Naftone, Inc., 74 Cust. Ct. 1,   C.D. 4578, affd., C.A.D. 1166, and Norton & Ellis, v. United States  52 Cust. Ct. 76, C.D.2440.


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  HOLDING:

       	Organofunctional silanes described are classifiable as other organoinorganic compunds in subheading 2931.00.50.   HTSUS.  The rate of duty is 3.7 percent ad valorem.

 						Sincerely,

                              				John Durant, Director
                              				Commercial Rulings Division