Method for processing a mineral filler with a phosphate, mineral fillers treated in this manner, polyurethane foams and composite polyurethanes using this filler, objects containing them which may or may not be moulded

A treated mineral filler of a specific grain size for the manufacture of polyurethane foams by a method whereby said filler is mixed with at least some of the polyol in the reaction forming the polyurethane and having a shorter mixing time with the polyol and the other reagents, characterised in that it

• a) is treated using at least one compound of the general formula (1):
• 4
• where R1=either H or alkyl with 8 to 40 carbon atoms or aryl or alkylaryl or arylalkyl with 6 to 40 carbon atoms
• where R2=either alkyl with 8 to 40 carbon atoms or aryl or alkylaryl or arylalkyl with 6 to 40 carbon atoms
• X=—CH2—CH2— or —CH(CH3)—CH2— or —CH2—CH(CH3) or —(CH2)5—CO—
• Y=—CH2—CH2— or —CH(CH3)—CH2—
• or —CH2—CH(CH3)— or —(CH2)5—CO—
• X and Y being the same or different,
• (m+n) varies from 0 to 60 (boundaries included) as well as (p+q) where 0≦m+n≦60 and 0≦p+q≦60 when X=Y=—CH2—CH2— and
• where (1≦m≦10 and 1≦p≦10) and (0≦n≦59 and 0≦q≦59) if X is different from Y.
• b) undergoes a de-agglomeration step and
• c) optionally undergoes a selection step.