摘要:
This invention relates to a method for boring a large-section tunnel safely and quickly by reinforcing and improving in advance the ground over the full length of the tunnel section, which includes; boring a top drift (2) through the full length of the tunnel (1) section, drilling curved holes inclined in forward or backward directions at an angle of about 45 degrees at preset intervals from the top drift (2) along the peripheral edges of the sections of the tunnel (1) by using ordinary small bore rock drills and curved steel pipes (3), pulling off the steel pipes (3) after inserting injection pipes into the drilled holes, injecting grout into the ground surrounding the tunnel through the injection pipes to develop artificial ground arches (4), excavating the tunnel (1), advancing suspension forms (6) and placing concrete for secondary lining.
摘要:
The present invention is intended to provide a technology preventing decrease in an electroconductivity or an throwing power of a cationic electrodeposition coating composition having a lower solid content and/or a lower ash content. Therefore, the present invention relates to: an electroconductivity-controlling agent used for a low solid content type cationic electrodeposition coating composition having 0.5 to 9.0 wt % of solid content of the coating composition, which agent includes an amino group-containing compound having 500 to 20000 of molecular weight and 200 to 500 mmol/100 g of amine value, to adjust an electroconductivity of the composition to 900 to 2000 μS/cm; a method for adjusting an electroconductivity of a cationic electrodeposition coating composition, which includes steps of: adding an electroconductivity-controlling agent to a low solid content type cationic electrodeposition coating composition having 0.5 to 9.0 wt % of solid content of the coating composition, and adjusting an electroconductivity of the cationic electrodeposition coating composition to 900 to 2000 μS/cm during the above step, wherein the electroconductivity-controlling agent includes an amino group-containing compound having 200 to 500 mmol/100 g of amine value; and the like.
摘要:
A cationic electrodeposition coating composition having superior defoaming property and being capable of effectively preventing the generation of unevennes of drying is provided. A cationic electrodeposition coating composition comprising a binder resin containing a cationic epoxy resin and a block isocyanate curing agent and a defoaming agent, wherein the defoaming agent contains at least one of polyoxyalkylene compounds (A) represented by any one of the following formulae (1) to (3): ]R—(OA)n1]t-mQ[—(OA)n2-L]m (1) [R—(OA)n1]t-mQ[—(OA)n2-L-(OA)n3-Q[—(OA)n4-R]t-1]m (2) [R—(OA)n1]t-1Q-L-Q [—(OA)n2-L]t-1 (3) wherein Q is a reaction residual group formed by removing a hydrogen atom(s) from a number t of primary hydroxyl groups of nonreducing disaccharide or trisaccharide, L is the reaction residual group of isocyanate or the reaction residual group of dihalogenated alkyl, OA is an oxyalkylene group having a carbon number of 2 to 4, each of n1 to n4 is independently an integer of 2 to 40, t is an integer of 2 to 4 and m is an integer of 1 to 3 and smaller than t, but provided that the total number of OA's in a molecule is 10 to 80 per one of Q.
摘要:
The present invention provides a method of forming a multilayer coating film comprising the step (I) of coating an article to be coated with an electrodeposition coating containing two resin components incompatible with each other followed by curing by heating to form an electrodeposited coating film, the step (II) of applying a water-borne intermediate coating onto the electrodeposited coating film to form an uncured intermediate coating film, the step (III) of applying a water-borne base coating onto the intermediate coating film to form an uncured base coating film, the step (IV) of applying a clear coating onto the base coating film to form an uncured clear coating film and the step (V) of curing the intermediate coating film, the base coating film and the clear coating film simultaneously by heating to thereby obtain a multilayer coating film.
摘要:
Disclosed is a coating method of intermediate-coating-less, which sufficiently keeps excellent appearance, weather resistance and corrosion resistance equal to a three layer coating in conventional technology. The method of the present invention comprises: electrocoating an aqueous paint composition comprising at least two sort of resins which are insoluble with each other, a curing agent and a pigment, on an electrically conductive substrate, heating it to form a layer separation, and then curing to form a plural layered cured coating having at least two layers, wherein a concentration of the pigment is distributed such that a pigment concentration (a) in the resin layer directly contacting air is relatively higher than a pigment concentration (b) in the resin layer directly contacting the electrically conductive substrate.