Field device of automation technology and method for its manufacture

Abstract

An epoxide polymer foam for a field device of automation technology comprising a measuring transducer for ascertaining a measurement signal and a measurement transmitter for output of a measurement signal ascertained, physical variable of a medium in a containment and/or a tube or pipe and/or a measurement signal ascertained property of the material of the medium, wherein the field device has at least one housing of the measuring transducer and/or of the measurement transmitter, in which electronic components of the measuring transducer and/or of the measurement transmitter are arranged, characterized in that the electronic components are embedded in an epoxide polymer foam, which is a reaction product of a self foaming, potting compound comprising at least the following components: 25 to 75 wt-% of a diglycidyl ether resin; at least one amine containing hardening system comprising a Mannich base; and at least one foaming agent, and a method for manufacturing a field device of automation technology.

1 - 11 . (canceled) 
     
     
         12 . An epoxide polymer foam for a field device of automation technology, comprising:
 a measuring transducer for ascertaining a measurement signal and a measurement transmitter for output of a measurement signal ascertained, physical variable of a medium in a containment and/or a tube or pipe and/or a measurement signal ascertained property of the material of the medium, wherein the field device further comprises at least one housing of the measuring transducer and/or of the measurement transmitter, in which electronic components of the measuring transducer and/or of the measurement transmitter are arranged, wherein the electronic components are embedded in the epoxide polymer foam, which is a reaction product of a self foaming, potting compound, comprising at least the following components:   a) 25 to 75 wt-% of a diglycidyl ether resin;   b) at least one amine containing hardening system comprising a Mannich base; and   c) at least one foaming agent.   
     
     
         13 . The epoxide polymer foam as claimed in  claim 12 , wherein:
 each of the components a)-c) is contained in the epoxide polymer foam with a residual content of greater than at least 100 ppm, preferably with a residual content of at least 500 ppm.   
     
     
         14 . The epoxide polymer foam as claimed in  claim 12 , wherein:
 the diglycidyl ether resin is a bisphenol-A- and/or bisphenol-F diglycidyl ether resin.   
     
     
         15 . The epoxide polymer foam as claimed in  claim 12 , wherein:
 the foaming agent is a polymethyl hydrosiloxane, which is preferably contained in the potting compound at up to 15 wt-%.   
     
     
         16 . The epoxide polymer foam as claimed in  claim 12 , wherein:
 the Mannich base is a reaction product of para-formaldehyde with 4-tert-butylphenol and/or a reaction product of 4,4′-isopropylidenediphenol with 1,3-phenylmethanamine, which is preferably contained in the potting compound at up to 15 wt-%.   
     
     
         17 . The epoxide polymer foam as claimed in  claim 12 , wherein:
 the potting compound additionally contains as an additional component   d) a reactive thinner, wherein the reactive thinner comprises preferably at least one aliphatic diglycylether with the general structural formula:   
       
         
           
           
               
               
           
         
       
       wherein R=butyl- or hexyl-. 
     
     
         18 . The epoxide polymer foam as claimed in  claim 12 , wherein:
 the potting compound additionally comprises as an additional component   e) a flame retarding and/or foam stabilizing filler, which preferably is an aluminum oxide, an aluminum hydroxide, a silicon oxide and/or a calcium carbonate.   
     
     
         19 . The epoxide polymer foam as claimed in  claim 18 , wherein:
 the potting compound additionally comprises as an additional component   f) a dispersion additive for stabilizing the filler in the potting compound.   
     
     
         20 . The epoxide polymer foam as claimed in  claim 12 , wherein:
 the potting compound, especially the hardening system, contains one or more of the following additional components:   g1) one or more fatty acids, preferably with a chain length of greater than C18, especially preferably unsaturated fatty acids with a chain length of greater than C18, especially in the form of dimers and/or oligomers;   g2) one or more reaction products with tall oil fatty acids and polyamines, preferably with TETA and/or TEPA;   g3) one or more polymers formed from a reaction of 4,4′-isopropylidenediphenol and/or 4,4′-methylene bisphenol with a reaction product of 1-chlorine-2,3-epoxypropane and 3-aminomethyl-3,5,5-trimethylcyclohexane and/or with a reaction product of 1-chlorine-2,3-epoxypropane and trimethylhexane-1,6-diamine;   g4) a trimethylhexane-1,6-diamine; 3-aminomethyl-3,5,5-trimethylcyclohexane and/or 1,3-phenylmethanamine;   g5) an aromatic alcohol, preferably 4,4′-isopropylidenediphenol, benzyl alcohol, salicylic acid, 4-tert.-butylphenol and/or phenol; and/or   g6) a liquid won from cashew nut shells.   
     
     
         21 . The epoxide polymer foam in  claim 12 , wherein
 the filler has two different granulations with a first grain size of 0.3 to 2.5 μm and a second grain size of 15 to 25 μm, wherein the ratio of filler with the first grain size to filler with the second grain size lies between 1 to 3 and 2 to 3.   
     
     
         22 . A method for manufacturing a field device of automation technology, comprising the steps as follows:
 a) arranging electronic components and, in given cases, further components of the field device within a housing of a measuring transducer and/or measurement transmitter;   b) introducing the flowable, self foaming, potting compound into the electronics housing to form an epoxide polymer foam; and   c) closing, especially medium tightly closing, the housing following a reaction time for foaming and   d) curing, i.e. hardening, the epoxide polymer foam and providing the operation ready field device.