How to identify insulating paper DMD and DMDM

DMD insulation paper full name is polyester film polyester fiber non-woven soft composite material, is a layer of polyester film coated with adhesive, one side for the polyester fiber non-woven composite, calendering made of a composite Insulation material products, referred to as DMD. There is a DMDM, then what is the difference between the two? give you the following:
      DM refers to two kinds of composite insulation paper, DMD refers to the three layers of composite insulation paper, where D is Dacron, refers to the polyester non-woven, that is, polyester or really good. M refers to a polyester film. DMD insulation paper is the outer two layers of polyester, the middle layer of polyester film, glue with glue from the composite products.
      The number of layers is different from the polyester film and polyester fiber nonwoven fabric with adhesive two to four layers of bonding between the two layers of DM, three for the DMD, four for the DMDM. Have a good mechanical, electrical performance, suitable for electrical appliances, tank insulation and liner insulation, heat-resistant grade of 130.